diff --git a/dropwizard-servlets/src/main/java/io/dropwizard/servlets/assets/AssetServlet.java b/dropwizard-servlets/src/main/java/io/dropwizard/servlets/assets/AssetServlet.java
index <HASH>..<HASH> 100644
--- a/dropwizard-servlets/src/main/java/io/dropwizard/servlets/assets/AssetServlet.java
+++ b/dropwizard-servlets/src/main/java/io/dropwizard/servlets/assets/AssetServlet.java
@@ -237,7 +237,9 @@ public class AssetServlet extends HttpServlet {
             resp.setDateHeader(LAST_MODIFIED, cachedAsset.getLastModifiedTime());
             resp.setHeader(ETAG, cachedAsset.getETag());
 
-            final String mediaType = Optional.ofNullable(req.getServletContext().getMimeType(req.getRequestURI()))
+            final String requestUri = req.getRequestURI();
+            final String mediaType = Optional.ofNullable(req.getServletContext().getMimeType(
+                    indexFile != null && requestUri.endsWith("/") ? requestUri + indexFile : requestUri))
                     .orElse(defaultMediaType);
             if (mediaType.startsWith("video") || mediaType.startsWith("audio") || usingRanges) {
                 resp.addHeader(ACCEPT_RANGES, "bytes");
AssetServlet: Use MIME type of index file for directory requests (#<I>)

With this change the extension of the index file is used do determine the content type of responses of requests to directories.