diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestEncoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestEncoder.java
index 2346205b34..5ff5af9c76 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestEncoder.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpRequestEncoder.java
@@ -26,6 +26,7 @@ import static io.netty.handler.codec.http.HttpConstants.*;
  */
 public class HttpRequestEncoder extends HttpObjectEncoder<HttpRequest> {
     private static final char SLASH = '/';
+    private static final char QUESTION_MARK = '?';
     private static final byte[] CRLF = { CR, LF };
 
     @Override
@@ -48,8 +49,22 @@ public class HttpRequestEncoder extends HttpObjectEncoder<HttpRequest> {
             int start = uri.indexOf("://");
             if (start != -1 && uri.charAt(0) != SLASH) {
                 int startIndex = start + 3;
-                if (uri.lastIndexOf(SLASH) <= startIndex) {
-                    uri += SLASH;
+                // Correctly handle query params.
+                // See https://github.com/netty/netty/issues/2732
+                int index = uri.indexOf(QUESTION_MARK, startIndex);
+                if (index == -1) {
+                    if (uri.lastIndexOf(SLASH) <= startIndex) {
+                        uri += SLASH;
+                    }
+                } else {
+                    if (uri.lastIndexOf(SLASH, index) <= startIndex) {
+                        int len = uri.length();
+                        StringBuilder sb = new StringBuilder(len + 1);
+                        sb.append(uri, 0, index);
+                        sb.append(SLASH);
+                        sb.append(uri, index, len);
+                        uri = sb.toString();
+                    }
                 }
             }
         }
diff --git a/codec-http/src/test/java/io/netty/handler/codec/http/HttpRequestEncoderTest.java b/codec-http/src/test/java/io/netty/handler/codec/http/HttpRequestEncoderTest.java
index 6ed9b95ff6..4852fe48eb 100644
--- a/codec-http/src/test/java/io/netty/handler/codec/http/HttpRequestEncoderTest.java
+++ b/codec-http/src/test/java/io/netty/handler/codec/http/HttpRequestEncoderTest.java
@@ -37,6 +37,16 @@ public class HttpRequestEncoderTest {
         assertEquals("GET http://localhost/ HTTP/1.1\r\n", req);
     }
 
+    @Test
+    public void testUriWithoutPath2() throws Exception {
+        HttpRequestEncoder encoder = new HttpRequestEncoder();
+        ByteBuf buffer = Unpooled.buffer(64);
+        encoder.encodeInitialLine(buffer, new DefaultHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET,
+                "http://localhost:9999?p1=v1"));
+        String req = buffer.toString(Charset.forName("US-ASCII"));
+        assertEquals("GET http://localhost:9999/?p1=v1 HTTP/1.1\r\n", req);
+    }
+
     @Test
     public void testUriWithPath() throws Exception {
         HttpRequestEncoder encoder = new HttpRequestEncoder();