Index: src/main/java/org/xwiki/rest/representations/comments/FormUrlEncodedCommentReader.java
===================================================================
--- src/main/java/org/xwiki/rest/representations/comments/FormUrlEncodedCommentReader.java	(revision 27780)
+++ src/main/java/org/xwiki/rest/representations/comments/FormUrlEncodedCommentReader.java	(working copy)
@@ -51,6 +51,8 @@
 public class FormUrlEncodedCommentReader implements MessageBodyReader<Comment>, XWikiRestComponent
 {
     private static final String COMMENT_TEXT_FIELD_NAME = "text";
+    
+    private static final String COMMENT_REPLYTO_FIELD_NAME = "replyTo";
 
     public boolean isReadable(Class< ? > type, Type genericType, Annotation[] annotations, MediaType mediaType)
     {
@@ -76,8 +78,10 @@
          * read data using getParameter()
          */
         if (form.getNames().isEmpty()) {
+            comment.setReplyTo(httpServletRequest.getParameter(COMMENT_REPLYTO_FIELD_NAME));
             comment.setText(httpServletRequest.getParameter(COMMENT_TEXT_FIELD_NAME));
         } else {
+            comment.setReplyTo(httpServletRequest.getParameter(COMMENT_REPLYTO_FIELD_NAME));
             comment.setText(form.getFirstValue(COMMENT_TEXT_FIELD_NAME));
         }
 
Index: src/main/java/org/xwiki/rest/DomainObjectFactory.java
===================================================================
--- src/main/java/org/xwiki/rest/DomainObjectFactory.java	(revision 27780)
+++ src/main/java/org/xwiki/rest/DomainObjectFactory.java	(working copy)
@@ -585,6 +585,11 @@
         if (property != null) {
             comment.setText((String) property.getValue());
         }
+        
+        property = xwikiComment.getProperty("replyto");
+        if (property != null) {
+            comment.setReplyTo((String) property.getValue());
+        }
 
         String pageUri =
             UriBuilder.fromUri(baseUri).path(PageResource.class).build(doc.getWiki(), doc.getSpace(), doc.getName())
Index: src/main/java/org/xwiki/rest/resources/comments/CommentsResource.java
===================================================================
--- src/main/java/org/xwiki/rest/resources/comments/CommentsResource.java	(revision 27780)
+++ src/main/java/org/xwiki/rest/resources/comments/CommentsResource.java	(working copy)
@@ -98,6 +98,11 @@
             save = true;
         }
 
+        if (comment.getReplyTo() != null) {
+            commentObject.set("replyto", comment.getReplyTo());
+            save = true;
+        }
+        
         if (save) {
             doc.save();
 
Index: src/main/resources/xwiki.rest.model.xsd
===================================================================
--- src/main/resources/xwiki.rest.model.xsd	(revision 27780)
+++ src/main/resources/xwiki.rest.model.xsd	(working copy)
@@ -181,6 +181,7 @@
           <element name="date" type="dateTime"></element>
           <element name="highlight" type="string"></element>
           <element name="text" type="string"></element>
+          <element name="replyTo" type="string"></element>
         </sequence>
       </extension>
     </complexContent>