diff --git a/app/assets/javascripts/discourse/dialects/bbcode_dialect.js b/app/assets/javascripts/discourse/dialects/bbcode_dialect.js
index 079bb014acb..b13441cfd14 100644
--- a/app/assets/javascripts/discourse/dialects/bbcode_dialect.js
+++ b/app/assets/javascripts/discourse/dialects/bbcode_dialect.js
@@ -169,11 +169,6 @@ Discourse.BBCode.replaceBBCodeParamsRaw("email", function(param, contents) {
   return ['a', {href: "mailto:" + param, 'data-bbcode': true}].concat(contents);
 });
 
-Discourse.BBCode.register('size', function(contents, params) {
-  return ['span', {'class': "bbcode-size-" + (parseInt(params, 10) || 1)}].concat(contents);
-});
-Discourse.Markdown.whiteListTag('span', 'class', /^bbcode-size-\d+$/);
-
 // Handles `[code] ... [/code]` blocks
 Discourse.Dialect.replaceBlock({
   start: /(\[code\])([\s\S]*)/igm,
diff --git a/app/assets/stylesheets/common/base/bbcode.scss b/app/assets/stylesheets/common/base/bbcode.scss
index b2ff87815b1..f40d8ac9a7f 100644
--- a/app/assets/stylesheets/common/base/bbcode.scss
+++ b/app/assets/stylesheets/common/base/bbcode.scss
@@ -13,10 +13,4 @@ span {
   &.bbcode-s {
     text-decoration: line-through;
   }
-  // Font sizes
-  @for $i from 4 through 40 {
-    &.bbcode-size-#{$i} {
-      font-size: #{$i}px;
-    }
-  }
 }
diff --git a/test/javascripts/lib/bbcode-test.js.es6 b/test/javascripts/lib/bbcode-test.js.es6
index 34b3992b843..86ca8d685e2 100644
--- a/test/javascripts/lib/bbcode-test.js.es6
+++ b/test/javascripts/lib/bbcode-test.js.es6
@@ -62,20 +62,6 @@ test('tags with arguments', function() {
   format("[b]first[/b] [b]second[/b]", "<span class=\"bbcode-b\">first</span> <span class=\"bbcode-b\">second</span>", "can bold two things on the same line");
 });
 
-test("size tags", function() {
-  format("[size=35]BIG [b]whoop[/b][/size]",
-         "<span class=\"bbcode-size-35\">BIG <span class=\"bbcode-b\">whoop</span></span>",
-         "supports [size=]");
-  format("[size=asdf]regular[/size]",
-         "<span class=\"bbcode-size-1\">regular</span>",
-         "it only supports numbers in bbcode");
-  format("[size=35]NEWLINE\n\ntest[/size]",
-         "<span class=\"bbcode-size-35\"><p>NEWLINE</p><p>test</p></span>",
-         "works with newlines");
-  format("[size=35][quote=\"user\"]quote[/quote][/size]",
-         "<span class=\"bbcode-size-35\"><aside class=\"quote\"><div class=\"title\"><div class=\"quote-controls\"></div>user:</div><blockquote><p>quote</p></blockquote></aside></span>",
-         "works with nested complex blocks");
-});
 
 test("quotes", function() {