diff --git a/core/src/main/java/com/google/googlejavaformat/java/Main.java b/core/src/main/java/com/google/googlejavaformat/java/Main.java
index 953ca5860..11c019234 100644
--- a/core/src/main/java/com/google/googlejavaformat/java/Main.java
+++ b/core/src/main/java/com/google/googlejavaformat/java/Main.java
@@ -79,7 +79,8 @@ static int main(PrintWriter out, PrintWriter err, String... args) {
       return formatter.format(args);
     } catch (UsageException e) {
       err.print(e.getMessage());
-      return 0;
+      // We return exit code 2 to differentiate usage issues from code formatting issues.
+      return 2;
     } finally {
       err.flush();
       out.flush();
diff --git a/core/src/test/java/com/google/googlejavaformat/java/GoogleJavaFormatToolProviderTest.java b/core/src/test/java/com/google/googlejavaformat/java/GoogleJavaFormatToolProviderTest.java
index 15e452297..d060fef1f 100644
--- a/core/src/test/java/com/google/googlejavaformat/java/GoogleJavaFormatToolProviderTest.java
+++ b/core/src/test/java/com/google/googlejavaformat/java/GoogleJavaFormatToolProviderTest.java
@@ -46,7 +46,7 @@ public void testUsageOutputAfterLoadingViaToolName() {
 
     int result = format.run(new PrintWriter(out, true), new PrintWriter(err, true), "--help");
 
-    assertThat(result).isEqualTo(0);
+    assertThat(result).isEqualTo(2);
 
     String usage = err.toString();
 
diff --git a/core/src/test/java/com/google/googlejavaformat/java/MainTest.java b/core/src/test/java/com/google/googlejavaformat/java/MainTest.java
index ac3eb3966..d4a410904 100644
--- a/core/src/test/java/com/google/googlejavaformat/java/MainTest.java
+++ b/core/src/test/java/com/google/googlejavaformat/java/MainTest.java
@@ -132,7 +132,7 @@ public void testMain() throws Exception {
     process.waitFor();
     String err = new String(ByteStreams.toByteArray(process.getErrorStream()), UTF_8);
     assertThat(err).contains("Usage: google-java-format");
-    assertThat(process.exitValue()).isEqualTo(0);
+    assertThat(process.exitValue()).isEqualTo(2);
   }
 
   // end to end javadoc formatting test