diff --git a/frontend_tests/node_tests/markdown.js b/frontend_tests/node_tests/markdown.js
index 7363723115..b00bf62f15 100644
--- a/frontend_tests/node_tests/markdown.js
+++ b/frontend_tests/node_tests/markdown.js
@@ -424,6 +424,16 @@ test("marked", () => {
             expected:
                 '<p>User group mention: <span class="user-group-mention" data-user-group-id="2">@Backend</span><br>\nUser group silent mention: <span class="user-group-mention silent" data-user-group-id="1">hamletcharacters</span></p>',
         },
+        {
+            input: "> User group mention in quote: @*backend*\n\n> Another user group mention in quote: @*hamletcharacters*",
+            expected:
+                '<blockquote>\n<p>User group mention in quote: <span class="user-group-mention silent" data-user-group-id="2">Backend</span></p>\n</blockquote>\n<blockquote>\n<p>Another user group mention in quote: <span class="user-group-mention silent" data-user-group-id="1">hamletcharacters</span></p>\n</blockquote>',
+        },
+        {
+            input: "```quote\nUser group mention in quote: @*backend*\n```\n\n```quote\nAnother user group mention in quote: @*hamletcharacters*\n```",
+            expected:
+                '<blockquote>\n<p>User group mention in quote: <span class="user-group-mention silent" data-user-group-id="2">Backend</span></p>\n</blockquote>\n<blockquote>\n<p>Another user group mention in quote: <span class="user-group-mention silent" data-user-group-id="1">hamletcharacters</span></p>\n</blockquote>',
+        },
         // Test only those linkifiers which don't return True for
         // `contains_backend_only_syntax()`. Those which return True
         // are tested separately.
@@ -740,6 +750,11 @@ test("message_flags", () => {
     message = {topic: "No links here", raw_content: input};
     markdown.apply_markdown(message);
     assert.equal(message.mentioned, false);
+
+    input = "> test @*hamletcharacters*";
+    message = {topic: "No links here", raw_content: input};
+    markdown.apply_markdown(message);
+    assert.equal(message.mentioned, false);
 });
 
 test("backend_only_linkifiers", () => {
diff --git a/static/js/markdown.js b/static/js/markdown.js
index 30f81011e3..67a57a66ea 100644
--- a/static/js/markdown.js
+++ b/static/js/markdown.js
@@ -224,6 +224,16 @@ export function apply_markdown(message) {
                 match = match.replace(/>@/g, ">");
                 return match;
             });
+
+            // Silence quoted user group mentions.
+            const user_group_re =
+                /<span[^>]*user-group-mention[^>]*data-user-group-id="\d+"[^>]*>@/gm;
+            quote = quote.replace(user_group_re, (match) => {
+                match = match.replace(/"user-group-mention"/g, '"user-group-mention silent"');
+                match = match.replace(/>@/g, ">");
+                return match;
+            });
+
             // In most cases, if you are being mentioned in the message you're quoting, you wouldn't
             // mention yourself outside of the blockquote (and, above it). If that you do that, the
             // following mentioned status is false; the backend rendering is authoritative and the