diff --git a/.changeset/six-cooks-battle.md b/.changeset/six-cooks-battle.md
new file mode 100644
index 0000000000..ecf856225e
--- /dev/null
+++ b/.changeset/six-cooks-battle.md
@@ -0,0 +1,6 @@
+---
+'@backstage/config-loader': patch
+'@backstage/config': patch
+---
+
+Allow colon to be used as config key.
diff --git a/packages/config-loader/src/sources/EnvConfigSource.ts b/packages/config-loader/src/sources/EnvConfigSource.ts
index d724f00c6d..988110b370 100644
--- a/packages/config-loader/src/sources/EnvConfigSource.ts
+++ b/packages/config-loader/src/sources/EnvConfigSource.ts
@@ -85,7 +85,7 @@ export class EnvConfigSource implements ConfigSource {
 const ENV_PREFIX = 'APP_CONFIG_';
 
 // Update the same pattern in config package if this is changed
-const CONFIG_KEY_PART_PATTERN = /^[a-z][a-z0-9]*(?:[-_][a-z0-9]+)*$/i;
+const CONFIG_KEY_PART_PATTERN = /^[a-z][a-z0-9]*(?:[-_:][a-z0-9]+)*$/i;
 
 /**
  * Read runtime configuration from the environment.
diff --git a/packages/config/src/reader.test.ts b/packages/config/src/reader.test.ts
index 3f6b9ac40a..bb16fbeaa1 100644
--- a/packages/config/src/reader.test.ts
+++ b/packages/config/src/reader.test.ts
@@ -43,6 +43,7 @@ const DATA = {
     null: null,
     string: 'string',
     strings: ['string1', 'string2'],
+    'with:colon': 'yes',
   },
   nestlings: [{ boolean: true }, { string: 'string' }, { number: 42 }] as {}[],
 };
@@ -57,6 +58,7 @@ function expectValidValues(config: ConfigReader) {
   expect(config.has('nested.one')).toBe(true);
   expect(config.has('nested.missing')).toBe(false);
   expect(config.has('nested.null')).toBe(false);
+  expect(config.has('nested.with:colon')).toBe(true);
   expect(config.getNumber('zero')).toBe(0);
   expect(config.getNumber('one')).toBe(1);
   expect(config.getNumber('zeroString')).toBe(0);
@@ -84,8 +86,11 @@ function expectValidValues(config: ConfigReader) {
     null: undefined,
     string: 'string',
     strings: ['string1', 'string2'],
+    'with:colon': 'yes',
   });
   expect(config.getConfig('nested').getString('string')).toBe('string');
+  expect(config.getString('nested.string')).toBe('string');
+  expect(config.getString('nested.with:colon')).toBe('yes');
   expect(config.getOptionalConfig('nested')!.getStringArray('strings')).toEqual(
     ['string1', 'string2'],
   );
diff --git a/packages/config/src/reader.ts b/packages/config/src/reader.ts
index 2e83de9bf2..7ad0cf738d 100644
--- a/packages/config/src/reader.ts
+++ b/packages/config/src/reader.ts
@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-import { JsonValue, JsonObject } from '@backstage/types';
+import { JsonObject, JsonValue } from '@backstage/types';
 import { AppConfig, Config } from './types';
 
 // Update the same pattern in config-loader package if this is changed
-const CONFIG_KEY_PART_PATTERN = /^[a-z][a-z0-9]*(?:[-_][a-z0-9]+)*$/i;
+const CONFIG_KEY_PART_PATTERN = /^[a-z][a-z0-9]*(?:[-_:][a-z0-9]+)*$/i;
 
 function isObject(value: JsonValue | undefined): value is JsonObject {
   return typeof value === 'object' && value !== null && !Array.isArray(value);