diff --git a/bp2build/android_test_conversion_test.go b/bp2build/android_test_conversion_test.go
index 52413fa..486f154 100644
--- a/bp2build/android_test_conversion_test.go
+++ b/bp2build/android_test_conversion_test.go
@@ -47,7 +47,40 @@
 		name: "TestApp",
 		srcs: ["app.java"],
 		sdk_version: "current",
+}
+`,
+		ExpectedBazelTargets: []string{
+			MakeBazelTarget("android_test", "TestApp", AttrNameToString{
+				"srcs":           `["app.java"]`,
+				"manifest":       `"AndroidManifest.xml"`,
+				"resource_files": `["res/res.png"]`,
+				"sdk_version":    `"current"`,
+				"assets":         `["assets/asset.png"]`,
+				"assets_dir":     `"assets"`,
+				// no need for optimize = False because it's false for
+				// android_test by default
+			}),
+		}})
+}
+
+func TestAndroidTest_OptimizationEnabled(t *testing.T) {
+	runAndroidAppTestCase(t, Bp2buildTestCase{
+		Description:                "Android test - simple example",
+		ModuleTypeUnderTest:        "android_test",
+		ModuleTypeUnderTestFactory: java.AndroidTestFactory,
+		Filesystem: map[string]string{
+			"app.java":            "",
+			"res/res.png":         "",
+			"AndroidManifest.xml": "",
+			"assets/asset.png":    "",
+		},
+		Blueprint: `
+android_test {
+		name: "TestApp",
+		srcs: ["app.java"],
+		sdk_version: "current",
 		optimize: {
+			enabled: true,
 			shrink: true,
 			optimize: true,
 			obfuscate: true,
@@ -62,6 +95,9 @@
 				"sdk_version":    `"current"`,
 				"assets":         `["assets/asset.png"]`,
 				"assets_dir":     `"assets"`,
+				// optimize = True because it's false for android_test by
+				// default
+				"optimize": `True`,
 			}),
 		}})
 }
@@ -98,6 +134,45 @@
 				"assets":         `["assets/asset.png"]`,
 				"assets_dir":     `"assets"`,
 				"testonly":       `True`,
+				// no need for optimize = True because it's true for
+				// android_test_helper_app by default
+			}),
+		}})
+}
+
+func TestAndroidTestHelperApp_OptimizationDisabled(t *testing.T) {
+	runAndroidAppTestCase(t, Bp2buildTestCase{
+		Description:                "Android test helper app - simple example",
+		ModuleTypeUnderTest:        "android_test_helper_app",
+		ModuleTypeUnderTestFactory: java.AndroidTestHelperAppFactory,
+		Filesystem: map[string]string{
+			"app.java":            "",
+			"res/res.png":         "",
+			"AndroidManifest.xml": "",
+			"assets/asset.png":    "",
+		},
+		Blueprint: `
+android_test_helper_app {
+		name: "TestApp",
+		srcs: ["app.java"],
+		sdk_version: "current",
+		optimize: {
+			enabled: false,
+		},
+}
+`,
+		ExpectedBazelTargets: []string{
+			MakeBazelTarget("android_binary", "TestApp", AttrNameToString{
+				"srcs":           `["app.java"]`,
+				"manifest":       `"AndroidManifest.xml"`,
+				"resource_files": `["res/res.png"]`,
+				"sdk_version":    `"current"`,
+				"assets":         `["assets/asset.png"]`,
+				"assets_dir":     `"assets"`,
+				"testonly":       `True`,
+				// optimize = False because it's true for
+				// android_test_helper_app by default
+				"optimize": `False`,
 			}),
 		}})
 }
diff --git a/java/app.go b/java/app.go
index 6030500..10ffa7a 100755
--- a/java/app.go
+++ b/java/app.go
@@ -1683,9 +1683,22 @@
 		Updatable:        a.appProperties.Updatable,
 	}
 
-	if !BoolDefault(a.dexProperties.Optimize.Enabled, true) {
-		appAttrs.Optimize = proptools.BoolPtr(false)
-	} else {
+	// Optimization is..
+	// - enabled by default for android_app, android_test_helper_app
+	// - disabled by default for android_test
+	//
+	// TODO(b/192032291): Disable android_test_helper_app optimization by
+	// default after auditing downstream usage.
+	if a.dexProperties.Optimize.Enabled == nil {
+		// Property was not explicitly defined.
+		a.dexProperties.Optimize.Enabled = &a.dexProperties.Optimize.EnabledByDefault
+	}
+	if Bool(a.dexProperties.Optimize.Enabled) {
+		if !a.dexProperties.Optimize.EnabledByDefault {
+			// explicitly enable optimize for module types that disable it by default
+			appAttrs.Optimize = proptools.BoolPtr(true)
+		}
+
 		handCraftedFlags := ""
 		if Bool(a.dexProperties.Optimize.Ignore_warnings) {
 			handCraftedFlags += "-ignorewarning "
@@ -1715,6 +1728,9 @@
 			})
 			appAttrs.Proguard_specs.Add(bazel.MakeLabelAttribute(":" + generatedFlagFileRuleName))
 		}
+	} else if a.dexProperties.Optimize.EnabledByDefault {
+		// explicitly disable optimize for module types that enable it by default
+		appAttrs.Optimize = proptools.BoolPtr(false)
 	}
 
 	commonAttrs, bp2BuildInfo, supported := a.convertLibraryAttrsBp2Build(ctx)
@@ -1803,13 +1819,12 @@
 		// an android_test_helper_app is an android_binary with testonly = True
 		commonAttrs.Testonly = proptools.BoolPtr(true)
 
-		// additionally, it sets default values differently to android_app,
+		// android_test_helper_app sets default values differently to android_app,
 		// https://cs.android.com/android/platform/superproject/main/+/main:build/soong/java/app.go;l=1273-1279;drc=e12c083198403ec694af6c625aed11327eb2bf7f
 		//
 		// installable: true (settable prop)
 		// use_embedded_native_libs: true (settable prop)
 		// lint.test: true (settable prop)
-		// optimize EnabledByDefault: true (blueprint mutated prop)
 		// AlwaysPackageNativeLibs: true (blueprint mutated prop)
 		// dexpreopt isTest: true (not prop)