diff --git a/media/css/readthedocs-doc-embed.css b/media/css/readthedocs-doc-embed.css
index d75e3ec4c74..8488690cfc8 100644
--- a/media/css/readthedocs-doc-embed.css
+++ b/media/css/readthedocs-doc-embed.css
@@ -161,3 +161,26 @@ div.ethical-sidebar, div.ethical-footer {
     display: table;
     margin-top: 3em;
 }
+
+/* Ad block nag */
+.keep-us-sustainable {
+    padding: .5em;
+    margin: 1em 0;
+    text-align: center;
+    border: 1px dotted #8ECC4C;
+}
+.keep-us-sustainable a,
+.keep-us-sustainable a:hover,
+.keep-us-sustainable a:visited {
+    text-decoration: none;
+}
+/* Read the Docs theme specific fixes */
+.wy-body-for-nav .keep-us-sustainable {
+    margin: 1em 2em 1em 1em;
+    color: #b3b3b3;
+}
+.wy-body-for-nav .keep-us-sustainable a {
+    color: #efefef;
+    font-size: 14px;
+    line-height: 20px;
+}
diff --git a/readthedocs/core/static-src/core/js/doc-embed/sponsorship.js b/readthedocs/core/static-src/core/js/doc-embed/sponsorship.js
index cd81e2137eb..2f0f0e34721 100644
--- a/readthedocs/core/static-src/core/js/doc-embed/sponsorship.js
+++ b/readthedocs/core/static-src/core/js/doc-embed/sponsorship.js
@@ -138,11 +138,28 @@ function adblock_admonition() {
     console.log(' - only show advertisements of interest to developers');
     console.log('Read more about our approach to advertising here: https://docs.readthedocs.io/en/latest/ethical-advertising.html');
     console.log('Read more about Ads for Open Source: https://ads-for-open-source.readthedocs.io');
+    console.log('Or go ad-free: https://readthedocs.org/sustainability/');
     console.log('%cPlease whitelist Read the Docs on your adblocker using the following filter:', 'font-size: 2em');
     console.log('https://ads-for-open-source.readthedocs.io/en/latest/_static/lists/readthedocs-ads.txt');
     console.log('--------------------------------------------------------------------------------------');
 }
 
+function adblock_nag() {
+    // Place an ad block nag into the sidebar
+    var placement = create_sidebar_placement();
+    var unblock_url = 'https://ads-for-open-source.readthedocs.io/';
+    var ad_free_url = 'https://readthedocs.org/sustainability/';
+    var container = null;
+
+    if (placement && placement.div_id) {
+        container = $('#' + placement.div_id).attr('class', 'keep-us-sustainable');
+
+        $('<p />').text('Support Read the Docs!').appendTo(container);
+        $('<p />').html('Please help keep us sustainable by <a href="' + unblock_url + '">allowing our Ethical Ads in your ad blocker</a> or <a href="' + ad_free_url + '">go ad-free</a> by subscribing.').appendTo(container);
+        $('<p />').text('Thank you! \u2764\ufe0f').appendTo(container);
+    }
+}
+
 function init() {
     var request_data = {format: "jsonp"};
     var div_ids = [];
@@ -207,6 +224,7 @@ function init() {
 
             if (xhr && xhr.status === 404 && rtd.api_host === 'https://readthedocs.org') {
                 adblock_admonition();
+                adblock_nag();
             }
         },
     });