diff --git a/translator/src/main/java/com/google/devtools/j2objc/gen/TypeDeclarationGenerator.java b/translator/src/main/java/com/google/devtools/j2objc/gen/TypeDeclarationGenerator.java
index 79179710a3..51b3de8dbd 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/gen/TypeDeclarationGenerator.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/gen/TypeDeclarationGenerator.java
@@ -135,7 +135,7 @@ protected void generateInitialDeclaration() {
       // refer to the companion type, so we need one forward declaration in any case.
       printf("\n@class %s;\n", typeName);
 
-      printf("\n@protocol %sCompanion\n", typeName);
+      printf("\n@protocol %sInternalCompanionProtocol\n", typeName);
       for (BodyDeclaration declaration : getInnerDeclarations()) {
         if (declaration.getKind().equals(TreeNode.Kind.METHOD_DECLARATION)) {
           printMethodDeclaration((MethodDeclaration) declaration, false, true);
@@ -162,7 +162,8 @@ protected void generateInitialDeclaration() {
       if (needsKotlinCompanionClass()) {
         printf("\n#pragma clang diagnostic push\n");
         printf("#pragma clang diagnostic ignored \"-Wincompatible-property-type\"\n");
-        printf("@property (readonly, class) id<%sCompanion> companion;\n", typeName);
+        printf(
+            "@property (readonly, class) id<%sInternalCompanionProtocol> companion;\n", typeName);
         printf("#pragma clang diagnostic pop\n");
       }
     }
@@ -485,7 +486,7 @@ protected void printCompanionClassDeclaration() {
     if (needsKotlinCompanionClass()) {
       printf("\n#pragma clang diagnostic push\n");
       printf("#pragma clang diagnostic ignored \"-Wincompatible-property-type\"\n");
-      printf("@property (readonly, class) id<%sCompanion> companion;\n", typeName);
+      printf("@property (readonly, class) id<%sInternalCompanionProtocol> companion;\n", typeName);
       printf("#pragma clang diagnostic pop\n");
     }
     println("\n@end");
diff --git a/translator/src/main/java/com/google/devtools/j2objc/gen/TypeImplementationGenerator.java b/translator/src/main/java/com/google/devtools/j2objc/gen/TypeImplementationGenerator.java
index 92d8debeb2..a026587146 100644
--- a/translator/src/main/java/com/google/devtools/j2objc/gen/TypeImplementationGenerator.java
+++ b/translator/src/main/java/com/google/devtools/j2objc/gen/TypeImplementationGenerator.java
@@ -118,8 +118,8 @@ protected void generate() {
       printf("@implementation %s\n", typeName);
       printProperties();
       if (needsKotlinCompanionClass()) {
-        printf("\n+ (id<%sCompanion>)companion {", typeName);
-        printf("\n  return (id<%sCompanion>)self;\n}\n", typeName);
+        printf("\n+ (id<%sInternalCompanionProtocol>)companion {", typeName);
+        printf("\n  return (id<%sInternalCompanionProtocol>)self;\n}\n", typeName);
       }
       printStaticAccessors();
       printInnerDeclarations();
diff --git a/translator/src/test/java/com/google/devtools/j2objc/gen/GenerateObjCCompanionTest.java b/translator/src/test/java/com/google/devtools/j2objc/gen/GenerateObjCCompanionTest.java
index e682bee231..87146571d7 100644
--- a/translator/src/test/java/com/google/devtools/j2objc/gen/GenerateObjCCompanionTest.java
+++ b/translator/src/test/java/com/google/devtools/j2objc/gen/GenerateObjCCompanionTest.java
@@ -36,14 +36,15 @@ public static void doSomething() {}
         """;
     String header = translateSourceFile(source, "Foo", "Foo.h");
     assertInTranslation(header, "@class Foo;");
-    assertInTranslation(header, "@protocol FooCompanion");
+    assertInTranslation(header, "@protocol FooInternalCompanionProtocol");
     // The companion protocol method should be an instance method instead of class method
     assertInTranslation(header, "- (void)doSomething;");
-    assertInTranslation(header, "@property (readonly, class) id<FooCompanion> companion;");
+    assertInTranslation(
+        header, "@property (readonly, class) id<FooInternalCompanionProtocol> companion;");
 
     String impl = translateSourceFile(source, "Foo", "Foo.m");
-    assertInTranslation(impl, "+ (id<FooCompanion>)companion {");
-    assertInTranslation(impl, "return (id<FooCompanion>)self;");
+    assertInTranslation(impl, "+ (id<FooInternalCompanionProtocol>)companion {");
+    assertInTranslation(impl, "return (id<FooInternalCompanionProtocol>)self;");
   }
 
   public void testGenericVariablesAreLost() throws IOException {
@@ -56,9 +57,10 @@ public class Bar<T> {
         """;
     String header = translateSourceFile(source, "Bar", "Bar.h");
     assertInTranslation(header, "@class Bar;");
-    assertInTranslation(header, "@protocol BarCompanion");
+    assertInTranslation(header, "@protocol BarInternalCompanionProtocol");
     assertInTranslation(header, "- (id)doSomethingWithId:(id)arg;");
-    assertInTranslation(header, "@property (readonly, class) id<BarCompanion> companion;");
+    assertInTranslation(
+        header, "@property (readonly, class) id<BarInternalCompanionProtocol> companion;");
   }
 
   public void testBoundGenericMethodTypesArePreserved() throws IOException {
@@ -73,7 +75,7 @@ public static ThreadLocal<String> identity(ThreadLocal<String> val) {
         """;
     String header = translateSourceFile(source, "Baz", "Baz.h");
     assertInTranslation(header, "@class Baz;");
-    assertInTranslation(header, "@protocol BazCompanion");
+    assertInTranslation(header, "@protocol BazInternalCompanionProtocol");
     assertInTranslation(
         header,
         "- (JavaLangThreadLocal<NSString *>"
@@ -92,7 +94,7 @@ public class Foo {
         }
         """;
     String header = translateSourceFile(source, "Foo", "Foo.h");
-    assertInTranslation(header, "@protocol FooCompanion");
+    assertInTranslation(header, "@protocol FooInternalCompanionProtocol");
     // Should generate instance property for CONSTANT_VALUE in companion protocol.
     assertInTranslation(
         header, "@property (readonly) int32_t CONSTANT_VALUE NS_SWIFT_NAME(CONSTANT_VALUE);");
@@ -114,7 +116,7 @@ public class Foo {
         """;
     // This should compile successfully without throwing "types without static methods" exception.
     String header = translateSourceFile(source, "Foo", "Foo.h");
-    assertInTranslation(header, "@protocol FooCompanion");
+    assertInTranslation(header, "@protocol FooInternalCompanionProtocol");
     assertInTranslation(
         header, "@property (readonly) int32_t CONSTANT_VALUE NS_SWIFT_NAME(CONSTANT_VALUE);");
   }
@@ -130,17 +132,18 @@ public static void doSomething() {}
         }
         """;
     String header = translateSourceFile(source, "Foo", "Foo.h");
-    assertInTranslation(header, "@protocol FooCompanion");
+    assertInTranslation(header, "@protocol FooInternalCompanionProtocol");
     assertInTranslation(
         header, "@property (readonly) int32_t CONSTANT_VALUE NS_SWIFT_NAME(CONSTANT_VALUE);");
     assertInTranslation(header, "- (void)doSomething;");
     assertInTranslation(header, "@interface Foo : NSObject");
-    assertInTranslation(header, "@property (readonly, class) id<FooCompanion> companion;");
+    assertInTranslation(
+        header, "@property (readonly, class) id<FooInternalCompanionProtocol> companion;");
 
     String impl = translateSourceFile(source, "Foo", "Foo.m");
     assertInTranslation(impl, "@implementation Foo");
-    assertInTranslation(impl, "+ (id<FooCompanion>)companion {");
-    assertInTranslation(impl, "return (id<FooCompanion>)self;");
+    assertInTranslation(impl, "+ (id<FooInternalCompanionProtocol>)companion {");
+    assertInTranslation(impl, "return (id<FooInternalCompanionProtocol>)self;");
   }
 
   public void testCompanionPropertiesForPropertyMethods() throws IOException {
@@ -156,7 +159,7 @@ public static String getBar() {
         }
         """;
     String header = translateSourceFile(source, "Foo", "Foo.h");
-    assertInTranslation(header, "@protocol FooCompanion");
+    assertInTranslation(header, "@protocol FooInternalCompanionProtocol");
     assertInTranslation(header, "@property (nonatomic, getter=getBar, readonly) NSString * bar;");
     assertInTranslation(
         header, "@property (class, nonatomic, getter=getBar, readonly) NSString * bar;");