diff --git a/apex/bootclasspath_fragment_test.go b/apex/bootclasspath_fragment_test.go
index b3f70cd..9965f83 100644
--- a/apex/bootclasspath_fragment_test.go
+++ b/apex/bootclasspath_fragment_test.go
@@ -141,6 +141,128 @@
 `)
 }
 
+func TestBootclasspathFragments_FragmentDependency(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		prepareForTestWithBootclasspathFragment,
+		// Configure some libraries in the art bootclasspath_fragment and platform_bootclasspath.
+		java.FixtureConfigureBootJars("com.android.art:baz", "com.android.art:quuz", "platform:foo", "platform:bar"),
+		prepareForTestWithArtApex,
+
+		java.PrepareForTestWithJavaSdkLibraryFiles,
+		java.FixtureWithLastReleaseApis("foo", "baz"),
+	).RunTestWithBp(t, `
+		java_sdk_library {
+			name: "foo",
+			srcs: ["b.java"],
+			shared_library: false,
+			public: {
+				enabled: true,
+			},
+			system: {
+				enabled: true,
+			},
+		}
+
+		java_library {
+			name: "bar",
+			srcs: ["b.java"],
+			installable: true,
+		}
+
+		apex {
+			name: "com.android.art",
+			key: "com.android.art.key",
+			bootclasspath_fragments: ["art-bootclasspath-fragment"],
+			updatable: false,
+		}
+
+		apex_key {
+			name: "com.android.art.key",
+			public_key: "com.android.art.avbpubkey",
+			private_key: "com.android.art.pem",
+		}
+
+		java_sdk_library {
+			name: "baz",
+			apex_available: [
+				"com.android.art",
+			],
+			srcs: ["b.java"],
+			shared_library: false,
+			public: {
+				enabled: true,
+			},
+			system: {
+				enabled: true,
+			},
+			test: {
+				enabled: true,
+			},
+		}
+
+		java_library {
+			name: "quuz",
+			apex_available: [
+				"com.android.art",
+			],
+			srcs: ["b.java"],
+			compile_dex: true,
+		}
+
+		bootclasspath_fragment {
+			name: "art-bootclasspath-fragment",
+			image_name: "art",
+			// Must match the "com.android.art:" entries passed to FixtureConfigureBootJars above.
+			contents: ["baz", "quuz"],
+			apex_available: [
+				"com.android.art",
+			],
+		}
+
+		bootclasspath_fragment {
+			name: "other-bootclasspath-fragment",
+			contents: ["foo", "bar"],
+			fragments: [
+					{
+							apex: "com.android.art",
+							module: "art-bootclasspath-fragment",
+					},
+			],
+		}
+`,
+	)
+
+	checkSdkKindStubs := func(message string, info java.HiddenAPIInfo, kind android.SdkKind, expectedPaths ...string) {
+		t.Helper()
+		android.AssertPathsRelativeToTopEquals(t, fmt.Sprintf("%s %s", message, kind), expectedPaths, info.TransitiveStubDexJarsByKind[kind])
+	}
+
+	// Check stub dex paths exported by art.
+	artFragment := result.Module("art-bootclasspath-fragment", "android_common")
+	artInfo := result.ModuleProvider(artFragment, java.HiddenAPIInfoProvider).(java.HiddenAPIInfo)
+
+	bazPublicStubs := "out/soong/.intermediates/baz.stubs/android_common/dex/baz.stubs.jar"
+	bazSystemStubs := "out/soong/.intermediates/baz.stubs.system/android_common/dex/baz.stubs.system.jar"
+	bazTestStubs := "out/soong/.intermediates/baz.stubs.test/android_common/dex/baz.stubs.test.jar"
+
+	checkSdkKindStubs("art", artInfo, android.SdkPublic, bazPublicStubs)
+	checkSdkKindStubs("art", artInfo, android.SdkSystem, bazSystemStubs)
+	checkSdkKindStubs("art", artInfo, android.SdkTest, bazTestStubs)
+	checkSdkKindStubs("art", artInfo, android.SdkCorePlatform)
+
+	// Check stub dex paths exported by other.
+	otherFragment := result.Module("other-bootclasspath-fragment", "android_common")
+	otherInfo := result.ModuleProvider(otherFragment, java.HiddenAPIInfoProvider).(java.HiddenAPIInfo)
+
+	fooPublicStubs := "out/soong/.intermediates/foo.stubs/android_common/dex/foo.stubs.jar"
+	fooSystemStubs := "out/soong/.intermediates/foo.stubs.system/android_common/dex/foo.stubs.system.jar"
+
+	checkSdkKindStubs("other", otherInfo, android.SdkPublic, bazPublicStubs, fooPublicStubs)
+	checkSdkKindStubs("other", otherInfo, android.SdkSystem, bazSystemStubs, fooSystemStubs)
+	checkSdkKindStubs("other", otherInfo, android.SdkTest, bazTestStubs, fooSystemStubs)
+	checkSdkKindStubs("other", otherInfo, android.SdkCorePlatform)
+}
+
 func checkBootclasspathFragment(t *testing.T, result *android.TestResult, moduleName string, expectedConfiguredModules string, expectedBootclasspathFragmentFiles string) {
 	t.Helper()
 
diff --git a/java/bootclasspath_fragment.go b/java/bootclasspath_fragment.go
index 0d61d82..db49df8 100644
--- a/java/bootclasspath_fragment.go
+++ b/java/bootclasspath_fragment.go
@@ -367,6 +367,11 @@
 	dexpreopt.RegisterToolDeps(ctx)
 }
 
+func (b *BootclasspathFragmentModule) BootclasspathDepsMutator(ctx android.BottomUpMutatorContext) {
+	// Add dependencies on all the fragments.
+	b.properties.BootclasspathFragmentsDepsProperties.addDependenciesOntoFragments(ctx)
+}
+
 func (b *BootclasspathFragmentModule) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	// Only perform a consistency check if this module is the active module. That will prevent an
 	// unused prebuilt that was created without instrumentation from breaking an instrumentation
@@ -387,8 +392,10 @@
 		}
 	})
 
+	fragments := gatherApexModulePairDepsWithTag(ctx, bootclasspathFragmentDepTag)
+
 	// Perform hidden API processing.
-	hiddenAPIFlagOutput := b.generateHiddenAPIBuildActions(ctx, contents)
+	hiddenAPIFlagOutput := b.generateHiddenAPIBuildActions(ctx, contents, fragments)
 
 	// Verify that the image_name specified on a bootclasspath_fragment is valid even if this is a
 	// prebuilt which will not use the image config.
@@ -502,10 +509,10 @@
 }
 
 // generateHiddenAPIBuildActions generates all the hidden API related build rules.
-func (b *BootclasspathFragmentModule) generateHiddenAPIBuildActions(ctx android.ModuleContext, contents []android.Module) *HiddenAPIFlagOutput {
+func (b *BootclasspathFragmentModule) generateHiddenAPIBuildActions(ctx android.ModuleContext, contents []android.Module, fragments []android.Module) *HiddenAPIFlagOutput {
 
 	// Create hidden API input structure.
-	input := b.createHiddenAPIFlagInput(ctx, contents)
+	input := b.createHiddenAPIFlagInput(ctx, contents, fragments)
 
 	var output *HiddenAPIFlagOutput
 
@@ -531,8 +538,10 @@
 		// perform its own flag generation.
 		FlagFilesByCategory: input.FlagFilesByCategory,
 
-		// Make these available for tests.
-		StubDexJarsByKind: input.StubDexJarsByKind,
+		// Other bootclasspath_fragments that depend on this need the transitive set of stub dex jars
+		// from this to resolve any references from their code to classes provided by this fragment
+		// and the fragments this depends upon.
+		TransitiveStubDexJarsByKind: input.transitiveStubDexJarsByKind(),
 	}
 
 	if output != nil {
@@ -549,7 +558,13 @@
 
 // createHiddenAPIFlagInput creates a HiddenAPIFlagInput struct and initializes it with information derived
 // from the properties on this module and its dependencies.
-func (b *BootclasspathFragmentModule) createHiddenAPIFlagInput(ctx android.ModuleContext, contents []android.Module) HiddenAPIFlagInput {
+func (b *BootclasspathFragmentModule) createHiddenAPIFlagInput(ctx android.ModuleContext, contents []android.Module, fragments []android.Module) HiddenAPIFlagInput {
+
+	// Merge the HiddenAPIInfo from all the fragment dependencies.
+	dependencyHiddenApiInfo := newHiddenAPIInfo()
+	dependencyHiddenApiInfo.mergeFromFragmentDeps(ctx, fragments)
+
+	// Create hidden API flag input structure.
 	input := newHiddenAPIFlagInput()
 
 	// Update the input structure with information obtained from the stub libraries.
@@ -558,6 +573,9 @@
 	// Populate with flag file paths from the properties.
 	input.extractFlagFilesFromProperties(ctx, &b.properties.Hidden_api)
 
+	// Store the stub dex jars from this module's fragment dependencies.
+	input.DependencyStubDexJarsByKind = dependencyHiddenApiInfo.TransitiveStubDexJarsByKind
+
 	return input
 }
 
diff --git a/java/bootclasspath_fragment_test.go b/java/bootclasspath_fragment_test.go
index f1c9077..581625d 100644
--- a/java/bootclasspath_fragment_test.go
+++ b/java/bootclasspath_fragment_test.go
@@ -264,17 +264,17 @@
 	otherPublicStubsJar := "out/soong/.intermediates/myothersdklibrary.stubs/android_common/dex/myothersdklibrary.stubs.jar"
 
 	// Check that SdkPublic uses public stubs for all sdk libraries.
-	android.AssertPathsRelativeToTopEquals(t, "public dex stubs jar", []string{otherPublicStubsJar, publicStubsJar, stubsJar}, info.StubDexJarsByKind[android.SdkPublic])
+	android.AssertPathsRelativeToTopEquals(t, "public dex stubs jar", []string{otherPublicStubsJar, publicStubsJar, stubsJar}, info.TransitiveStubDexJarsByKind[android.SdkPublic])
 
 	// Check that SdkSystem uses system stubs for mysdklibrary and public stubs for myothersdklibrary
 	// as it does not provide system stubs.
-	android.AssertPathsRelativeToTopEquals(t, "system dex stubs jar", []string{otherPublicStubsJar, systemStubsJar, stubsJar}, info.StubDexJarsByKind[android.SdkSystem])
+	android.AssertPathsRelativeToTopEquals(t, "system dex stubs jar", []string{otherPublicStubsJar, systemStubsJar, stubsJar}, info.TransitiveStubDexJarsByKind[android.SdkSystem])
 
 	// Check that SdkTest also uses system stubs for mysdklibrary as it does not provide test stubs
 	// and public stubs for myothersdklibrary as it does not provide test stubs either.
-	android.AssertPathsRelativeToTopEquals(t, "test dex stubs jar", []string{otherPublicStubsJar, systemStubsJar, stubsJar}, info.StubDexJarsByKind[android.SdkTest])
+	android.AssertPathsRelativeToTopEquals(t, "test dex stubs jar", []string{otherPublicStubsJar, systemStubsJar, stubsJar}, info.TransitiveStubDexJarsByKind[android.SdkTest])
 
 	// Check that SdkCorePlatform uses public stubs from the mycoreplatform library.
 	corePlatformStubsJar := "out/soong/.intermediates/mycoreplatform.stubs/android_common/dex/mycoreplatform.stubs.jar"
-	android.AssertPathsRelativeToTopEquals(t, "core platform dex stubs jar", []string{corePlatformStubsJar}, info.StubDexJarsByKind[android.SdkCorePlatform])
+	android.AssertPathsRelativeToTopEquals(t, "core platform dex stubs jar", []string{corePlatformStubsJar}, info.TransitiveStubDexJarsByKind[android.SdkCorePlatform])
 }
diff --git a/java/hiddenapi_modular.go b/java/hiddenapi_modular.go
index 94fe2ca..3707942 100644
--- a/java/hiddenapi_modular.go
+++ b/java/hiddenapi_modular.go
@@ -67,6 +67,12 @@
 
 // hiddenAPIRelevantSdkKinds lists all the android.SdkKind instances that are needed by the hidden
 // API processing.
+//
+// These are in order from narrowest API surface to widest. Widest means the API stubs with the
+// biggest API surface, e.g. test is wider than system is wider than public. Core platform is
+// considered wider than test even though it has no relationship with test because the libraries
+// that provide core platform API don't provide test. While the core platform API is being converted
+// to a system API the system API is still a subset of core platform.
 var hiddenAPIRelevantSdkKinds = []android.SdkKind{
 	android.SdkPublic,
 	android.SdkSystem,
@@ -164,14 +170,30 @@
 
 	tempPath := tempPathForRestat(ctx, outputPath)
 
+	// Find the widest API stubs provided by the fragments on which this depends, if any.
+	var dependencyStubDexJars android.Paths
+	for i := len(hiddenAPIRelevantSdkKinds) - 1; i >= 0; i-- {
+		kind := hiddenAPIRelevantSdkKinds[i]
+		stubsForKind := input.DependencyStubDexJarsByKind[kind]
+		if len(stubsForKind) != 0 {
+			dependencyStubDexJars = stubsForKind
+			break
+		}
+	}
+
 	command := rule.Command().
 		Tool(ctx.Config().HostToolPath(ctx, "hiddenapi")).
 		Text("list").
+		FlagForEachInput("--dependency-stub-dex=", dependencyStubDexJars).
 		FlagForEachInput("--boot-dex=", bootDexJars)
 
 	// Iterate over the sdk kinds in a fixed order.
 	for _, sdkKind := range hiddenAPIRelevantSdkKinds {
-		paths := input.StubDexJarsByKind[sdkKind]
+		// Merge in the stub dex jar paths for this kind from the fragments on which it depends. They
+		// will be needed to resolve dependencies from this fragment's stubs to classes in the other
+		// fragment's APIs.
+		dependencyPaths := input.DependencyStubDexJarsByKind[sdkKind]
+		paths := append(dependencyPaths, input.StubDexJarsByKind[sdkKind]...)
 		if len(paths) > 0 {
 			option := sdkKindToHiddenapiListOption[sdkKind]
 			command.FlagWithInputList("--"+option+"=", paths, ":")
@@ -349,12 +371,34 @@
 	FlagFilesByCategory FlagFilesByCategory
 
 	// The paths to the stub dex jars for each of the android.SdkKind in hiddenAPIRelevantSdkKinds.
-	StubDexJarsByKind StubDexJarsByKind
+	TransitiveStubDexJarsByKind StubDexJarsByKind
 
 	// The output from the hidden API processing needs to be made available to other modules.
 	HiddenAPIFlagOutput
 }
 
+func newHiddenAPIInfo() *HiddenAPIInfo {
+	info := HiddenAPIInfo{
+		FlagFilesByCategory:         FlagFilesByCategory{},
+		TransitiveStubDexJarsByKind: StubDexJarsByKind{},
+	}
+	return &info
+}
+
+func (i *HiddenAPIInfo) mergeFromFragmentDeps(ctx android.ModuleContext, fragments []android.Module) {
+	// Merge all the information from the fragments. The fragments form a DAG so it is possible that
+	// this will introduce duplicates so they will be resolved after processing all the fragments.
+	for _, fragment := range fragments {
+		if ctx.OtherModuleHasProvider(fragment, HiddenAPIInfoProvider) {
+			info := ctx.OtherModuleProvider(fragment, HiddenAPIInfoProvider).(HiddenAPIInfo)
+			i.TransitiveStubDexJarsByKind.append(info.TransitiveStubDexJarsByKind)
+		}
+	}
+
+	// Dedup and sort paths.
+	i.TransitiveStubDexJarsByKind.dedupAndSort()
+}
+
 var HiddenAPIInfoProvider = blueprint.NewProvider(HiddenAPIInfo{})
 
 // StubDexJarsByKind maps an android.SdkKind to the paths to stub dex jars appropriate for that
@@ -387,6 +431,11 @@
 	// StubDexJarsByKind contains the stub dex jars for different android.SdkKind and which determine
 	// the initial flags for each dex member.
 	StubDexJarsByKind StubDexJarsByKind
+
+	// DependencyStubDexJarsByKind contains the stub dex jars provided by the fragments on which this
+	// depends. It is the result of merging HiddenAPIInfo.TransitiveStubDexJarsByKind from each
+	// fragment on which this depends.
+	DependencyStubDexJarsByKind StubDexJarsByKind
 }
 
 // newHiddenAPIFlagInput creates a new initialize HiddenAPIFlagInput struct.
@@ -480,6 +529,12 @@
 	}
 }
 
+func (i *HiddenAPIFlagInput) transitiveStubDexJarsByKind() StubDexJarsByKind {
+	transitive := i.DependencyStubDexJarsByKind
+	transitive.append(i.StubDexJarsByKind)
+	return transitive
+}
+
 // HiddenAPIFlagOutput contains paths to output files from the hidden API flag generation for a
 // bootclasspath_fragment module.
 type HiddenAPIFlagOutput struct {