diff --git a/src/spec-configuration/containerFeaturesConfiguration.ts b/src/spec-configuration/containerFeaturesConfiguration.ts
index e0094202a..4e1c2f05c 100644
--- a/src/spec-configuration/containerFeaturesConfiguration.ts
+++ b/src/spec-configuration/containerFeaturesConfiguration.ts
@@ -71,10 +71,16 @@ export interface Mount {
 	external?: boolean;
 }
 
+const normalizedMountKeys: Record<string, string> = {
+	src: 'source',
+	destination: 'target',
+	dst: 'target',
+};
+
 export function parseMount(str: string): Mount {
 	return str.split(',')
 		.map(s => s.split('='))
-		.reduce((acc, [key, value]) => ({ ...acc, [key]: value }), {}) as Mount;
+		.reduce((acc, [key, value]) => ({ ...acc, [(normalizedMountKeys[key] || key)]: value }), {}) as Mount;
 }
 
 export type SourceInformation = LocalCacheSourceInformation | GithubSourceInformation | DirectTarballSourceInformation | FilePathSourceInformation | OCISourceInformation;
diff --git a/src/spec-node/imageMetadata.ts b/src/spec-node/imageMetadata.ts
index ba7a42908..37de895fd 100644
--- a/src/spec-node/imageMetadata.ts
+++ b/src/spec-node/imageMetadata.ts
@@ -5,7 +5,7 @@
 
 import { ContainerError } from '../spec-common/errors';
 import { DevContainerConfig, DevContainerConfigCommand, DevContainerFromDockerComposeConfig, DevContainerFromDockerfileConfig, DevContainerFromImageConfig, getDockerComposeFilePaths, getDockerfilePath, HostRequirements, isDockerFileConfig, PortAttributes, UserEnvProbe } from '../spec-configuration/configuration';
-import { Feature, FeaturesConfig, Mount } from '../spec-configuration/containerFeaturesConfiguration';
+import { Feature, FeaturesConfig, Mount, parseMount } from '../spec-configuration/containerFeaturesConfiguration';
 import { ContainerDetails, DockerCLIParameters, ImageDetails } from '../spec-shutdown/dockerUtils';
 import { Log } from '../spec-utils/log';
 import { getBuildInfoForService, readDockerComposeConfig } from './dockerCompose';
@@ -125,7 +125,7 @@ export function mergeConfiguration(config: DevContainerConfig, imageMetadata: Im
 		capAdd: unionOrUndefined(imageMetadata.map(entry => entry.capAdd)),
 		securityOpt: unionOrUndefined(imageMetadata.map(entry => entry.securityOpt)),
 		entrypoints: collectOrUndefined(imageMetadata, 'entrypoint'),
-		mounts: concatOrUndefined(imageMetadata.map(entry => entry.mounts)),
+		mounts: mergeMounts(imageMetadata),
 		customizations: Object.keys(customizations).length ? customizations : undefined,
 		onCreateCommands: collectOrUndefined(imageMetadata, 'onCreateCommand'),
 		updateContentCommands: collectOrUndefined(imageMetadata, 'updateContentCommand'),
@@ -181,9 +181,20 @@ function parseBytes(str: string) {
 	return 0;
 }
 
-function concatOrUndefined<T>(entries: (T[] | undefined)[]): T[] | undefined {
-	const values = ([] as T[]).concat(...entries.filter(entry => !!entry) as T[][]);
-	return values.length ? values : undefined;
+function mergeMounts(imageMetadata: ImageMetadataEntry[]): (Mount | string)[] | undefined {
+	const seen = new Set<string>();
+	const mounts = imageMetadata.map(entry => entry.mounts)
+		.filter(Boolean)
+		.flat()
+		.map(mount => ({
+			obj: typeof mount === 'string' ? parseMount(mount) : mount!,
+			orig: mount!,
+		}))
+		.reverse()
+		.filter(mount => !seen.has(mount.obj.target) && seen.add(mount.obj.target))
+		.reverse()
+		.map(mount => mount.orig);
+	return mounts.length ? mounts : undefined;
 }
 
 function unionOrUndefined<T>(entries: (T[] | undefined)[]): T[] | undefined {
diff --git a/src/test/imageMetadata.test.ts b/src/test/imageMetadata.test.ts
index 544478330..4dc8899c2 100644
--- a/src/test/imageMetadata.test.ts
+++ b/src/test/imageMetadata.test.ts
@@ -6,7 +6,7 @@
 import * as assert from 'assert';
 import * as path from 'path';
 import { URI } from 'vscode-uri';
-import { Feature, FeaturesConfig, FeatureSet } from '../spec-configuration/containerFeaturesConfiguration';
+import { Feature, FeaturesConfig, FeatureSet, Mount } from '../spec-configuration/containerFeaturesConfiguration';
 import { experimentalImageMetadataDefault } from '../spec-node/devContainers';
 import { getDevcontainerMetadata, getDevcontainerMetadataLabel, getImageMetadata, getImageMetadataFromContainer, imageMetadataLabel, mergeConfiguration } from '../spec-node/imageMetadata';
 import { SubstitutedConfig } from '../spec-node/utils';
@@ -244,6 +244,46 @@ describe('Image Metadata', function () {
 			assert.strictEqual(merged.remoteEnv?.ENV3, 'devcontainer.json');
 			assert.strictEqual(merged.remoteEnv?.ENV4, 'feature1');
 		});
+
+		it('should deduplicate mounts', () => {
+			const merged = mergeConfiguration({
+				configFilePath: URI.parse('file:///devcontainer.json'),
+				image: 'image',
+			}, [
+				{
+					mounts: [
+						'source=source1,dst=target1,type=volume',
+						'source=source2,target=target2,type=volume',
+						'source=source3,destination=target3,type=volume',
+					],
+				},
+				{
+					mounts: [
+						{
+							source: 'source4',
+							target: 'target1',
+							type: 'volume'
+						},
+					],
+				},
+				{
+					mounts: [
+						{
+							source: 'source5',
+							target: 'target3',
+							type: 'volume'
+						},
+					],
+				},
+			]);
+			assert.strictEqual(merged.mounts?.length, 3);
+			assert.strictEqual(typeof merged.mounts?.[0], 'string');
+			assert.strictEqual(merged.mounts?.[0], 'source=source2,target=target2,type=volume');
+			assert.strictEqual(typeof merged.mounts?.[1], 'object');
+			assert.strictEqual((merged.mounts?.[1] as Mount).source, 'source4');
+			assert.strictEqual(typeof merged.mounts?.[2], 'object');
+			assert.strictEqual((merged.mounts?.[2] as Mount).source, 'source5');
+		});
 	});
 });