diff --git a/.changeset/funny-areas-rescue.md b/.changeset/funny-areas-rescue.md
new file mode 100644
index 0000000000..0b13201f82
--- /dev/null
+++ b/.changeset/funny-areas-rescue.md
@@ -0,0 +1,7 @@
+---
+'@backstage/ui': minor
+---
+
+Add support for flex item props (`grow`, `shrink`, and `basis`) to `Box`, `Card`, `Grid`, and `Flex` itself.
+
+**Affected components:** Box, Card, Grid, Flex
diff --git a/packages/ui/report.api.md b/packages/ui/report.api.md
index 4856387abf..b3cdc5ced4 100644
--- a/packages/ui/report.api.md
+++ b/packages/ui/report.api.md
@@ -431,6 +431,9 @@ export const BoxDefinition: {
     'py',
     'position',
     'display',
+    'grow',
+    'shrink',
+    'basis',
     'width',
     'minWidth',
     'maxWidth',
@@ -452,6 +455,7 @@ export type BoxOwnProps = {
 // @public (undocumented)
 export interface BoxProps
   extends SpaceProps,
+    FlexItemProps,
     BoxOwnProps,
     BoxUtilityProps,
     Omit<React.HTMLAttributes<HTMLDivElement>, 'children'> {}
@@ -642,6 +646,7 @@ export const Card: ForwardRefExoticComponent<
 export type CardBaseProps = {
   children?: ReactNode;
   className?: string;
+  style?: CSSProperties;
 };
 
 // @public
@@ -702,7 +707,9 @@ export const CardDefinition: {
     readonly target: {};
     readonly rel: {};
     readonly download: {};
+    readonly style: {};
   };
+  readonly utilityProps: readonly ['grow', 'shrink', 'basis'];
 };
 
 // @public
@@ -786,10 +793,12 @@ export type CardOwnProps = Pick<
   | 'target'
   | 'rel'
   | 'download'
+  | 'style'
 >;
 
 // @public
 export type CardProps = CardBaseProps &
+  FlexItemProps &
   Omit<React.HTMLAttributes<HTMLDivElement>, 'onClick'> &
   (CardButtonVariant | CardLinkVariant | CardStaticVariant);
 
@@ -1315,12 +1324,22 @@ export const FlexDefinition: {
     'align',
     'justify',
     'direction',
+    'grow',
+    'shrink',
+    'basis',
   ];
 };
 
 // @public (undocumented)
 export type FlexDirection = 'row' | 'column';
 
+// @public
+export interface FlexItemProps {
+  basis?: Responsive<CSSProperties['flexBasis']>;
+  grow?: Responsive<number | boolean>;
+  shrink?: Responsive<number | boolean>;
+}
+
 // @public (undocumented)
 export type FlexOwnProps = {
   children: ReactNode;
@@ -1332,6 +1351,7 @@ export type FlexOwnProps = {
 // @public (undocumented)
 export interface FlexProps
   extends SpaceProps,
+    FlexItemProps,
     FlexOwnProps,
     Omit<React.HTMLAttributes<HTMLDivElement>, 'children'> {
   // (undocumented)
@@ -1422,6 +1442,9 @@ export const GridDefinition: {
     'pt',
     'px',
     'py',
+    'grow',
+    'shrink',
+    'basis',
   ];
 };
 
@@ -1478,6 +1501,7 @@ export type GridOwnProps = {
 // @public (undocumented)
 export interface GridProps
   extends SpaceProps,
+    FlexItemProps,
     GridOwnProps,
     Omit<HTMLAttributes<HTMLDivElement>, 'children'> {
   // (undocumented)
diff --git a/packages/ui/src/components/Box/Box.tsx b/packages/ui/src/components/Box/Box.tsx
index 146292a344..1a2930dd2b 100644
--- a/packages/ui/src/components/Box/Box.tsx
+++ b/packages/ui/src/components/Box/Box.tsx
@@ -36,7 +36,7 @@ export const Box = forwardRef<HTMLDivElement, BoxProps>((props, ref) => {
     {
       ref,
       className: classes.root,
-      style: { ...ownProps.style, ...utilityStyle },
+      style: { ...utilityStyle, ...ownProps.style },
       ...dataAttributes,
       ...restProps,
     },
diff --git a/packages/ui/src/components/Box/definition.ts b/packages/ui/src/components/Box/definition.ts
index 3837dc8ea4..c3a38326b2 100644
--- a/packages/ui/src/components/Box/definition.ts
+++ b/packages/ui/src/components/Box/definition.ts
@@ -52,6 +52,9 @@ export const BoxDefinition = defineComponent<BoxOwnProps>()({
     'py',
     'position',
     'display',
+    'grow',
+    'shrink',
+    'basis',
     'width',
     'minWidth',
     'maxWidth',
diff --git a/packages/ui/src/components/Box/types.ts b/packages/ui/src/components/Box/types.ts
index 1b4259099b..e333690e2e 100644
--- a/packages/ui/src/components/Box/types.ts
+++ b/packages/ui/src/components/Box/types.ts
@@ -15,7 +15,12 @@
  */
 
 import type { ReactNode, CSSProperties } from 'react';
-import type { Responsive, ProviderBg, SpaceProps } from '../../types';
+import type {
+  Responsive,
+  ProviderBg,
+  SpaceProps,
+  FlexItemProps,
+} from '../../types';
 
 /** @public */
 export type BoxOwnProps = {
@@ -43,6 +48,7 @@ export type BoxUtilityProps = {
 /** @public */
 export interface BoxProps
   extends SpaceProps,
+    FlexItemProps,
     BoxOwnProps,
     BoxUtilityProps,
     Omit<React.HTMLAttributes<HTMLDivElement>, 'children'> {}
diff --git a/packages/ui/src/components/Card/Card.tsx b/packages/ui/src/components/Card/Card.tsx
index aecca09512..498fd5b021 100644
--- a/packages/ui/src/components/Card/Card.tsx
+++ b/packages/ui/src/components/Card/Card.tsx
@@ -41,7 +41,7 @@ const INTERACTIVE_ELEMENT_SELECTOR =
  * @public
  */
 export const Card = forwardRef<HTMLDivElement, CardProps>((props, ref) => {
-  const { ownProps, restProps, dataAttributes } = useDefinition(
+  const { ownProps, restProps, dataAttributes, utilityStyle } = useDefinition(
     CardDefinition,
     props,
   );
@@ -98,6 +98,7 @@ export const Card = forwardRef<HTMLDivElement, CardProps>((props, ref) => {
       {...dataAttributes}
       {...restProps}
       onClick={isInteractive ? handleClick : undefined}
+      style={{ ...utilityStyle, ...ownProps.style }}
     >
       {href && (
         <Link
diff --git a/packages/ui/src/components/Card/definition.ts b/packages/ui/src/components/Card/definition.ts
index 5d69005b4c..f2012f9a7c 100644
--- a/packages/ui/src/components/Card/definition.ts
+++ b/packages/ui/src/components/Card/definition.ts
@@ -42,7 +42,9 @@ export const CardDefinition = defineComponent<CardOwnProps>()({
     target: {},
     rel: {},
     download: {},
+    style: {},
   },
+  utilityProps: ['grow', 'shrink', 'basis'],
 });
 
 /**
diff --git a/packages/ui/src/components/Card/types.ts b/packages/ui/src/components/Card/types.ts
index 5809384c16..83daf2de08 100644
--- a/packages/ui/src/components/Card/types.ts
+++ b/packages/ui/src/components/Card/types.ts
@@ -14,11 +14,16 @@
  * limitations under the License.
  */
 
-import type { ReactNode } from 'react';
+import type { ReactNode, CSSProperties } from 'react';
 import type { ButtonProps as RAButtonProps } from 'react-aria-components';
+import type { FlexItemProps } from '../../types';
 
 /** @public */
-export type CardBaseProps = { children?: ReactNode; className?: string };
+export type CardBaseProps = {
+  children?: ReactNode;
+  className?: string;
+  style?: CSSProperties;
+};
 
 /** @public */
 export type CardButtonVariant = {
@@ -63,6 +68,7 @@ export type CardStaticVariant = {
  * @public
  */
 export type CardProps = CardBaseProps &
+  FlexItemProps &
   Omit<React.HTMLAttributes<HTMLDivElement>, 'onClick'> &
   (CardButtonVariant | CardLinkVariant | CardStaticVariant);
 
@@ -81,6 +87,7 @@ export type CardOwnProps = Pick<
   | 'target'
   | 'rel'
   | 'download'
+  | 'style'
 >;
 
 /** @public */
diff --git a/packages/ui/src/components/Flex/Flex.stories.tsx b/packages/ui/src/components/Flex/Flex.stories.tsx
index 91d4088004..b392b6e731 100644
--- a/packages/ui/src/components/Flex/Flex.stories.tsx
+++ b/packages/ui/src/components/Flex/Flex.stories.tsx
@@ -16,7 +16,9 @@
 import preview from '../../../../../.storybook/preview';
 import { Flex } from './Flex';
 import { Text } from '../Text';
-import { Box } from '../Box';
+import { Box, BoxProps } from '../Box';
+import { Card, CardHeader, CardBody, CardFooter } from '../Card';
+import { Grid } from '../Grid';
 
 const meta = preview.meta({
   title: 'Backstage UI/Flex',
@@ -41,10 +43,9 @@ const meta = preview.meta({
 const DecorativeBox = ({
   width = '48px',
   height = '48px',
-}: {
-  width?: string;
-  height?: string;
-}) => {
+  style,
+  ...props
+}: Omit<BoxProps, 'children'>) => {
   const diagonalStripePattern = (() => {
     const svg = `
       <svg width="6" height="6" viewBox="0 0 6 6" xmlns="http://www.w3.org/2000/svg">
@@ -58,9 +59,11 @@ const DecorativeBox = ({
 
   return (
     <Box
+      {...props}
       width={width}
       height={height}
       style={{
+        ...style,
         background: '#eaf2fd',
         borderRadius: '4px',
         border: '1px solid #2563eb',
@@ -199,6 +202,122 @@ export const ResponsiveAlign = meta.story({
   ),
 });
 
+export const FlexItems = meta.story({
+  args: {
+    component: 'Box',
+    grow: 1,
+    shrink: 0,
+    basis: 'auto',
+  },
+  argTypes: {
+    component: {
+      control: { type: 'select' },
+      options: ['Box', 'Card', 'Grid', 'Flex'],
+      mapping: {
+        Box: props => <DecorativeBox height="100%" width="256px" {...props} />,
+        Card: props => (
+          <Card style={{ height: '100%', width: '256px' }} {...props}>
+            <CardHeader>
+              <Text>Header</Text>
+            </CardHeader>
+            <CardBody>
+              <Text>
+                This is the first paragraph of a long body text that
+                demonstrates how the Card component handles extensive content.
+                The card should adjust accordingly to display all the text
+                properly while maintaining its structure.
+              </Text>
+              <Text>
+                Here's a second paragraph that adds more content to our card
+                body. Having multiple paragraphs helps to visualize how spacing
+                works within the card component.
+              </Text>
+              <Text>
+                This third paragraph continues to add more text to ensure we
+                have a proper demonstration of a card with significant content.
+                This makes it easier to test scrolling behavior and overall
+                layout when content exceeds the initial view.
+              </Text>
+            </CardBody>
+            <CardFooter>
+              <Text>Footer</Text>
+            </CardFooter>
+          </Card>
+        ),
+        Grid: props => (
+          <Grid.Root
+            {...props}
+            height="128px"
+            style={{ width: '256px' }}
+            columns="3"
+          >
+            <Grid.Item colSpan="1" rowSpan="2">
+              <DecorativeBox height="100%" width="100%" />
+            </Grid.Item>
+            <Grid.Item colSpan="2">
+              <DecorativeBox height="100%" width="100%" />
+            </Grid.Item>
+            <Grid.Item colSpan="2">
+              <DecorativeBox height="100%" width="100%" />
+            </Grid.Item>
+          </Grid.Root>
+        ),
+        Flex: props => (
+          <Flex
+            {...props}
+            height="128px"
+            style={{ width: '256px' }}
+            justify="between"
+          >
+            <DecorativeBox height="100%" />
+            <DecorativeBox height="100%" />
+            <DecorativeBox height="100%" />
+          </Flex>
+        ),
+      },
+    },
+    grow: {
+      control: 'radio',
+      options: [undefined, 0, 1, false, true],
+    },
+    shrink: {
+      control: 'radio',
+      options: [undefined, 0, 1, false, true],
+    },
+    basis: {
+      control: 'radio',
+      options: [undefined, '0%', '25%', '50%', '100%', 100, '250px', 'auto'],
+    },
+  },
+  render: ({ component: Component, ...args }) => {
+    return (
+      <Flex style={{ width: '100%', height: '256px' }}>
+        <div
+          style={{
+            width: '256px',
+            flex: '1 1 auto',
+            background:
+              'repeating-linear-gradient(-45deg, transparent 0px, transparent 5px, #e8e8e8 5px, #e8e8e8 10px)',
+            borderRadius: '12px',
+          }}
+        />
+
+        <Component {...args} />
+
+        <div
+          style={{
+            width: '256px',
+            flex: '1 1 auto',
+            background:
+              'repeating-linear-gradient(-45deg, transparent 0px, transparent 5px, #e8e8e8 5px, #e8e8e8 10px)',
+            borderRadius: '12px',
+          }}
+        />
+      </Flex>
+    );
+  },
+});
+
 export const ResponsiveGap = meta.story({
   args: {
     gap: { xs: '4', md: '8', lg: '12' },
diff --git a/packages/ui/src/components/Flex/definition.ts b/packages/ui/src/components/Flex/definition.ts
index 802464c4e1..1bc9c54217 100644
--- a/packages/ui/src/components/Flex/definition.ts
+++ b/packages/ui/src/components/Flex/definition.ts
@@ -53,5 +53,8 @@ export const FlexDefinition = defineComponent<FlexOwnProps>()({
     'align',
     'justify',
     'direction',
+    'grow',
+    'shrink',
+    'basis',
   ],
 });
diff --git a/packages/ui/src/components/Flex/types.ts b/packages/ui/src/components/Flex/types.ts
index 1c7f887e62..5b295e1825 100644
--- a/packages/ui/src/components/Flex/types.ts
+++ b/packages/ui/src/components/Flex/types.ts
@@ -15,7 +15,13 @@
  */
 
 import type { ReactNode, CSSProperties } from 'react';
-import type { Responsive, Space, SpaceProps, ProviderBg } from '../../types';
+import type {
+  Responsive,
+  Space,
+  SpaceProps,
+  ProviderBg,
+  FlexItemProps,
+} from '../../types';
 
 /** @public */
 export type FlexOwnProps = {
@@ -28,6 +34,7 @@ export type FlexOwnProps = {
 /** @public */
 export interface FlexProps
   extends SpaceProps,
+    FlexItemProps,
     FlexOwnProps,
     Omit<React.HTMLAttributes<HTMLDivElement>, 'children'> {
   gap?: Responsive<Space>;
diff --git a/packages/ui/src/components/Grid/definition.ts b/packages/ui/src/components/Grid/definition.ts
index 606b286b3c..2d83e9db6a 100644
--- a/packages/ui/src/components/Grid/definition.ts
+++ b/packages/ui/src/components/Grid/definition.ts
@@ -51,6 +51,9 @@ export const GridDefinition = defineComponent<GridOwnProps>()({
     'pt',
     'px',
     'py',
+    'grow',
+    'shrink',
+    'basis',
   ],
 });
 
diff --git a/packages/ui/src/components/Grid/types.ts b/packages/ui/src/components/Grid/types.ts
index 6ad5d564c6..90699c59d2 100644
--- a/packages/ui/src/components/Grid/types.ts
+++ b/packages/ui/src/components/Grid/types.ts
@@ -21,6 +21,7 @@ import type {
   Responsive,
   Columns,
   ProviderBg,
+  FlexItemProps,
 } from '../../types';
 
 /** @public */
@@ -34,6 +35,7 @@ export type GridOwnProps = {
 /** @public */
 export interface GridProps
   extends SpaceProps,
+    FlexItemProps,
     GridOwnProps,
     Omit<HTMLAttributes<HTMLDivElement>, 'children'> {
   columns?: Responsive<Columns>;
diff --git a/packages/ui/src/css/utilities/flex.css b/packages/ui/src/css/utilities/flex.css
index 2248addfee..bf5bf392cd 100644
--- a/packages/ui/src/css/utilities/flex.css
+++ b/packages/ui/src/css/utilities/flex.css
@@ -67,6 +67,18 @@
     flex-direction: column-reverse;
   }
 
+  .bui-grow {
+    flex-grow: var(--grow);
+  }
+
+  .bui-shrink {
+    flex-shrink: var(--shrink);
+  }
+
+  .bui-basis {
+    flex-basis: var(--basis);
+  }
+
   /* Breakpoint xs */
   @media (min-width: 640px) {
     .xs\:bui-align-start {
@@ -116,6 +128,18 @@
     .xs\:bui-fd-column-reverse {
       flex-direction: column-reverse;
     }
+
+    .xs\:bui-grow {
+      flex-grow: var(--grow-xs);
+    }
+
+    .xs\:bui-shrink {
+      flex-shrink: var(--shrink-xs);
+    }
+
+    .xs\:bui-basis {
+      flex-basis: var(--basis-xs);
+    }
   }
 
   /* Breakpoint sm */
@@ -167,6 +191,18 @@
     .sm\:bui-fd-column-reverse {
       flex-direction: column-reverse;
     }
+
+    .sm\:bui-grow {
+      flex-grow: var(--grow-sm);
+    }
+
+    .sm\:bui-shrink {
+      flex-shrink: var(--shrink-sm);
+    }
+
+    .sm\:bui-basis {
+      flex-basis: var(--basis-sm);
+    }
   }
 
   /* Breakpoint md */
@@ -218,6 +254,18 @@
     .md\:bui-fd-column-reverse {
       flex-direction: column-reverse;
     }
+
+    .md\:bui-grow {
+      flex-grow: var(--grow-md);
+    }
+
+    .md\:bui-shrink {
+      flex-shrink: var(--shrink-md);
+    }
+
+    .md\:bui-basis {
+      flex-basis: var(--basis-md);
+    }
   }
 
   /* Breakpoint lg */
@@ -269,6 +317,18 @@
     .lg\:bui-fd-column-reverse {
       flex-direction: column-reverse;
     }
+
+    .lg\:bui-grow {
+      flex-grow: var(--grow-lg);
+    }
+
+    .lg\:bui-shrink {
+      flex-shrink: var(--shrink-lg);
+    }
+
+    .lg\:bui-basis {
+      flex-basis: var(--basis-lg);
+    }
   }
 
   /* Breakpoint xl */
@@ -320,5 +380,17 @@
     .xl\:bui-fd-column-reverse {
       flex-direction: column-reverse;
     }
+
+    .xl\:bui-grow {
+      flex-grow: var(--grow-xl);
+    }
+
+    .xl\:bui-shrink {
+      flex-shrink: var(--shrink-xl);
+    }
+
+    .xl\:bui-basis {
+      flex-basis: var(--basis-xl);
+    }
   }
 }
diff --git a/packages/ui/src/hooks/useDefinition/helpers.ts b/packages/ui/src/hooks/useDefinition/helpers.ts
index 8a990b4b6a..2169a26238 100644
--- a/packages/ui/src/hooks/useDefinition/helpers.ts
+++ b/packages/ui/src/hooks/useDefinition/helpers.ts
@@ -102,7 +102,7 @@ export function processUtilityProps<Keys extends string>(
 
   const handleUtilityValue = (
     key: string,
-    val: unknown,
+    inputVal: unknown,
     prefix: string = '',
   ) => {
     // Get utility class configuration for this key
@@ -113,6 +113,11 @@ export function processUtilityProps<Keys extends string>(
       return;
     }
 
+    const val =
+      'transform' in utilityConfig
+        ? utilityConfig.transform(inputVal)
+        : inputVal;
+
     // Check if value is in the list of valid values for this utility
     const values = utilityConfig.values as readonly (string | number)[];
     if (values.length > 0 && values.includes(val as string | number)) {
diff --git a/packages/ui/src/types.ts b/packages/ui/src/types.ts
index 113eb06a5c..3a6633bc37 100644
--- a/packages/ui/src/types.ts
+++ b/packages/ui/src/types.ts
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+import type { CSSProperties } from 'react';
+
 /** @public */
 export type Breakpoint = 'initial' | 'xs' | 'sm' | 'md' | 'lg' | 'xl';
 
@@ -120,6 +122,20 @@ export interface PaddingProps {
 /** @public */
 export interface SpaceProps extends MarginProps, PaddingProps {}
 
+/**
+ * Flex item properties.
+ *
+ * @public
+ */
+export interface FlexItemProps {
+  /** Controls the flex-grow property. Values of `true` or `false` are converted to `1` or `0` respectively. */
+  grow?: Responsive<number | boolean>;
+  /** Controls the flex-shrink property. Values of `true` or `false` are converted to `1` or `0` respectively. */
+  shrink?: Responsive<number | boolean>;
+  /** Controls the flex-basis property. */
+  basis?: Responsive<CSSProperties['flexBasis']>;
+}
+
 /** @public */
 export type TextVariants =
   | 'title-large'
diff --git a/packages/ui/src/utils/utilityClassMap.ts b/packages/ui/src/utils/utilityClassMap.ts
index f70052d588..2b8106eef2 100644
--- a/packages/ui/src/utils/utilityClassMap.ts
+++ b/packages/ui/src/utils/utilityClassMap.ts
@@ -196,7 +196,30 @@ export const utilityClassMap = {
     class: 'bui-row-span',
     values: columnsValues,
   },
+  grow: {
+    class: 'bui-grow',
+    cssVar: '--grow',
+    values: [],
+    transform: input => (typeof input === 'boolean' ? Number(input) : input),
+  },
+  shrink: {
+    class: 'bui-shrink',
+    cssVar: '--shrink',
+    values: [],
+    transform: input => (typeof input === 'boolean' ? Number(input) : input),
+  },
+  basis: {
+    class: 'bui-basis',
+    cssVar: '--basis',
+    values: [],
+    transform: input => (typeof input === 'number' ? `${input}px` : input),
+  },
 } as const satisfies Record<
   string,
-  { class: string; cssVar?: string; values: readonly (string | number)[] }
+  {
+    class: string;
+    cssVar?: string;
+    values: readonly (string | number)[];
+    transform?: (input: unknown) => unknown;
+  }
 >;