diff --git a/plugins/catalog-backend/src/catalog/types.ts b/plugins/catalog-backend/src/catalog/types.ts
index 3f74f2ee98..2a18783679 100644
--- a/plugins/catalog-backend/src/catalog/types.ts
+++ b/plugins/catalog-backend/src/catalog/types.ts
@@ -25,6 +25,7 @@ import { Entity, EntityRelationSpec } from '@backstage/catalog-model';
 export type EntityFilter =
   | { allOf: EntityFilter[] }
   | { anyOf: EntityFilter[] }
+  | { not: EntityFilter }
   | EntitiesSearchFilter;
 
 /**
@@ -39,7 +40,7 @@ export type EntityPagination = {
 /**
  * Matches rows in the entities_search table.
  */
-export type EntitiesValuesFilter = {
+export type EntitiesSearchFilter = {
   /**
    * The key to match on.
    *
@@ -50,28 +51,12 @@ export type EntitiesValuesFilter = {
   /**
    * Match on plain equality of values.
    *
-   * Match on
-   * values that are equal to any of the given array items. Matches are always
-   * case insensitive.
+   * Match on values that are equal to any of the given array items. Matches are
+   * always case insensitive.
    */
-  values: string[];
-
-  negate?: boolean;
+  values?: string[];
 };
 
-export type EntitiesKeyFilter = {
-  /**
-   * The key to match on.
-   *
-   * Matches are always case insensitive.
-   */
-  key: string;
-
-  negate?: boolean;
-};
-
-export type EntitiesSearchFilter = EntitiesValuesFilter | EntitiesKeyFilter;
-
 export type PageInfo =
   | {
       hasNextPage: false;
diff --git a/plugins/catalog-backend/src/service/NextEntitiesCatalog.test.ts b/plugins/catalog-backend/src/service/NextEntitiesCatalog.test.ts
index 32d5fa843e..c968b6de82 100644
--- a/plugins/catalog-backend/src/service/NextEntitiesCatalog.test.ts
+++ b/plugins/catalog-backend/src/service/NextEntitiesCatalog.test.ts
@@ -282,7 +282,6 @@ describe('NextEntitiesCatalog', () => {
 
         const testFilter = {
           key: 'spec.test',
-          matchValueExists: true,
         };
         const request = { filter: testFilter };
         const { entities } = await catalog.entities(request);
@@ -292,6 +291,41 @@ describe('NextEntitiesCatalog', () => {
       },
     );
 
+    it.each(databases.eachSupportedId())(
+      'should return correct entity for negation filter',
+      async databaseId => {
+        const { knex } = await createDatabase(databaseId);
+        const entity1: Entity = {
+          apiVersion: 'a',
+          kind: 'k',
+          metadata: { name: 'one' },
+          spec: {},
+        };
+        const entity2: Entity = {
+          apiVersion: 'a',
+          kind: 'k',
+          metadata: { name: 'two' },
+          spec: {
+            test: 'test value',
+          },
+        };
+        await addEntityToSearch(knex, entity1);
+        await addEntityToSearch(knex, entity2);
+        const catalog = new NextEntitiesCatalog(knex);
+
+        const testFilter = {
+          not: {
+            key: 'spec.test',
+          },
+        };
+        const request = { filter: testFilter };
+        const { entities } = await catalog.entities(request);
+
+        expect(entities.length).toBe(1);
+        expect(entities[0]).toEqual(entity1);
+      },
+    );
+
     it.each(databases.eachSupportedId())(
       'should return correct entity for nested filter',
       async databaseId => {
@@ -328,24 +362,27 @@ describe('NextEntitiesCatalog', () => {
 
         const testFilter1 = {
           key: 'metadata.org',
-          matchValueExists: true,
-          matchValueIn: ['b'],
+          values: ['b'],
         };
         const testFilter2 = {
           key: 'metadata.desc',
-          matchValueExists: true,
         };
         const testFilter3 = {
           key: 'metadata.color',
-          matchValueExists: true,
-          matchValueIn: ['blue'],
+          values: ['blue'],
+        };
+        const testFilter4 = {
+          not: {
+            key: 'metadata.color',
+            values: ['red'],
+          },
         };
         const request = {
           filter: {
             allOf: [
               testFilter1,
               {
-                anyOf: [testFilter2, testFilter3],
+                anyOf: [testFilter2, testFilter3, testFilter4],
               },
             ],
           },
diff --git a/plugins/catalog-backend/src/service/NextEntitiesCatalog.ts b/plugins/catalog-backend/src/service/NextEntitiesCatalog.ts
index 1c615f862a..ccce1395d7 100644
--- a/plugins/catalog-backend/src/service/NextEntitiesCatalog.ts
+++ b/plugins/catalog-backend/src/service/NextEntitiesCatalog.ts
@@ -78,33 +78,30 @@ function stringifyPagination(input: { limit: number; offset: number }) {
 function addCondition(
   queryBuilder: Knex.QueryBuilder,
   db: Knex,
-  { key, matchValueIn, matchValueExists }: EntitiesSearchFilter,
+  filter: EntitiesSearchFilter,
+  negate: boolean = false,
 ) {
   // NOTE(freben): This used to be a set of OUTER JOIN, which may seem to
   // make a lot of sense. However, it had abysmal performance on sqlite
   // when datasets grew large, so we're using IN instead.
   const matchQuery = db<DbSearchRow>('search')
     .select('entity_id')
-    .where(function keyFilter() {
-      this.andWhere({ key: key.toLowerCase() });
-      if (matchValueExists !== false && matchValueIn) {
-        if (matchValueIn.length === 1) {
-          this.andWhere({ value: matchValueIn[0].toLowerCase() });
-        } else if (matchValueIn.length > 1) {
+    .where({ key: filter.key.toLowerCase() })
+    .andWhere(function keyFilter() {
+      if (filter.values) {
+        if (filter.values.length === 1) {
+          this.where({ value: filter.values[0].toLowerCase() });
+        } else if (filter.values.length > 1) {
           this.andWhere(
             'value',
             'in',
-            matchValueIn.map(v => v.toLowerCase()),
+            filter.values.map(v => v.toLowerCase()),
           );
         }
       }
     });
   // Explicitly evaluate matchValueExists as a boolean since it may be undefined
-  queryBuilder.andWhere(
-    'entity_id',
-    matchValueExists === false ? 'not in' : 'in',
-    matchQuery,
-  );
+  queryBuilder.andWhere('entity_id', negate ? 'not in' : 'in', matchQuery);
 }
 
 function isEntitiesSearchFilter(
@@ -125,21 +122,32 @@ function isOrEntityFilter(
   return filter.hasOwnProperty('anyOf');
 }
 
+function isNegationEntityFilter(
+  filter: { not: EntityFilter } | EntityFilter,
+): filter is { not: EntityFilter } {
+  return filter.hasOwnProperty('not');
+}
+
 function parseFilter(
   filter: EntityFilter,
   query: Knex.QueryBuilder,
   db: Knex,
+  negate: boolean = false,
 ): Knex.QueryBuilder {
   if (isEntitiesSearchFilter(filter)) {
     return query.andWhere(function filterFunction() {
-      addCondition(this, db, filter);
+      addCondition(this, db, filter, negate);
     });
   }
 
+  if (isNegationEntityFilter(filter)) {
+    return parseFilter(filter.not, query, db, true);
+  }
+
   if (isOrEntityFilter(filter)) {
     return query.andWhere(function filterFunction() {
       for (const subFilter of filter.anyOf ?? []) {
-        this.orWhere(subQuery => parseFilter(subFilter, subQuery, db));
+        this.orWhere(subQuery => parseFilter(subFilter, subQuery, db, negate));
       }
     });
   }
@@ -147,7 +155,7 @@ function parseFilter(
   if (isAndEntityFilter(filter)) {
     return query.andWhere(function filterFunction() {
       for (const subFilter of filter.allOf ?? []) {
-        this.andWhere(subQuery => parseFilter(subFilter, subQuery, db));
+        this.andWhere(subQuery => parseFilter(subFilter, subQuery, db, negate));
       }
     });
   }