diff --git a/src/main/resources/winstone/mime.properties b/src/main/resources/winstone/mime.properties
index e5768c1b..76b659ab 100644
--- a/src/main/resources/winstone/mime.properties
+++ b/src/main/resources/winstone/mime.properties
@@ -279,7 +279,8 @@ gtm=application/vnd.groove-tool-message
 gtw=model/vnd.gtw
 gv=text/vnd.graphviz
 gxt=application/vnd.geonext
-gz=application/x-gzip
+gz=application/gzip
+gzip=application/gzip
 h261=video/h261
 h263=video/h263
 h264=video/h264
@@ -765,6 +766,7 @@ sxw=application/vnd.sun.xml.writer
 taglet=application/vnd.mynfc
 tao=application/vnd.tao.intent-module-archive
 tar=application/x-tar
+tar.gz=application/gzip
 tcap=application/vnd.3gpp2.tcap
 tcl=application/x-tcl
 teacher=application/vnd.smart.teacher
@@ -776,7 +778,7 @@ texinfo=application/x-texinfo
 text=text/plain
 tfi=application/thraud+xml
 tfm=application/x-tex-tfm
-tgz=application/x-gzip
+tgz=application/x-gtar
 thmx=application/vnd.ms-officetheme
 tiff=image/tiff
 tif=image/tiff
diff --git a/src/test/java/winstone/LauncherTest.java b/src/test/java/winstone/LauncherTest.java
index b4e99d14..577b26ce 100644
--- a/src/test/java/winstone/LauncherTest.java
+++ b/src/test/java/winstone/LauncherTest.java
@@ -17,6 +17,7 @@
 import java.util.zip.GZIPInputStream;
 import org.eclipse.jetty.server.ServerConnector;
 import org.junit.Test;
+import org.jvnet.hudson.test.Issue;
 
 /**
  * @author Kohsuke Kawaguchi
@@ -97,4 +98,27 @@ public void mimeType() throws Exception {
         assertEquals("text/xxx", response.headers().firstValue("Content-Type").get());
         assertEquals("Hello", response.body());
     }
+
+    @Issue("JENKINS-60409")
+    @Test
+    public void doubleGzip() throws Exception {
+        Map<String, String> args = new HashMap<>();
+        args.put("warfile", "target/test-classes/test.war");
+        args.put("prefix", "/");
+        args.put("httpPort", "0");
+        winstone = new Launcher(args);
+        int port = ((ServerConnector) winstone.server.getConnectors()[0]).getLocalPort();
+        HttpRequest request = HttpRequest.newBuilder(new URI("http://127.0.0.2:" + port + "/lipsum.tar.gz"))
+                .header("Accept-Encoding", "gzip")
+                .GET()
+                .build();
+        HttpResponse<byte[]> response =
+                HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofByteArray());
+        assertEquals(HttpURLConnection.HTTP_OK, response.statusCode());
+        assertEquals(
+                "application/gzip",
+                response.headers().firstValue("Content-Type").orElseThrow());
+        assertFalse(response.headers().firstValue("Content-Encoding").isPresent());
+        assertEquals(1345, response.body().length);
+    }
 }
diff --git a/src/testwebapp/lipsum.tar.gz b/src/testwebapp/lipsum.tar.gz
new file mode 100644
index 00000000..8d7ecfd0
Binary files /dev/null and b/src/testwebapp/lipsum.tar.gz differ