diff --git a/dom/base/nsContentSink.cpp b/dom/base/nsContentSink.cpp
index 85b3d07bf8..490f0ec17c 100644
--- a/dom/base/nsContentSink.cpp
+++ b/dom/base/nsContentSink.cpp
@@ -304,7 +304,8 @@ nsContentSink::ProcessHeaderData(nsIAtom* aHeader, const nsAString& aValue,
 
   mDocument->SetHeaderData(aHeader, aValue);
 
-  if (aHeader == nsGkAtoms::setcookie) {
+  if (aHeader == nsGkAtoms::setcookie &&
+      Preferences::GetBool("dom.meta-set-cookie.enabled", true)) {
     // Don't allow setting cookies in cookie-averse documents.
     if (mDocument->IsCookieAverse()) {
       return NS_OK;
diff --git a/extensions/cookie/test/file_domain_hierarchy_inner.html b/extensions/cookie/test/file_domain_hierarchy_inner.html
index 1a37345975..a62e1b9e42 100644
--- a/extensions/cookie/test/file_domain_hierarchy_inner.html
+++ b/extensions/cookie/test/file_domain_hierarchy_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta=tag">
   <script type="text/javascript">
     document.cookie = "can=has";
 
diff --git a/extensions/cookie/test/file_domain_hierarchy_inner.html^headers^ b/extensions/cookie/test/file_domain_hierarchy_inner.html^headers^
new file mode 100644
index 0000000000..993cedb908
--- /dev/null
+++ b/extensions/cookie/test/file_domain_hierarchy_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta=tag
diff --git a/extensions/cookie/test/file_domain_hierarchy_inner_inner.html b/extensions/cookie/test/file_domain_hierarchy_inner_inner.html
index 3075b971a5..9b8f1a2f33 100644
--- a/extensions/cookie/test/file_domain_hierarchy_inner_inner.html
+++ b/extensions/cookie/test/file_domain_hierarchy_inner_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta2=tag2">
   <script type="text/javascript">
     document.cookie = "can2=has2";
 
diff --git a/extensions/cookie/test/file_domain_hierarchy_inner_inner.html^headers^ b/extensions/cookie/test/file_domain_hierarchy_inner_inner.html^headers^
new file mode 100644
index 0000000000..405494cd6e
--- /dev/null
+++ b/extensions/cookie/test/file_domain_hierarchy_inner_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta2=tag2
diff --git a/extensions/cookie/test/file_domain_hierarchy_inner_inner_inner.html b/extensions/cookie/test/file_domain_hierarchy_inner_inner_inner.html
index e8d09338b3..d306efb1c0 100644
--- a/extensions/cookie/test/file_domain_hierarchy_inner_inner_inner.html
+++ b/extensions/cookie/test/file_domain_hierarchy_inner_inner_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta3=tag3">
   <script type="text/javascript">
     document.cookie = "can3=has3";
 
diff --git a/extensions/cookie/test/file_domain_hierarchy_inner_inner_inner.html^headers^ b/extensions/cookie/test/file_domain_hierarchy_inner_inner_inner.html^headers^
new file mode 100644
index 0000000000..add3336ec9
--- /dev/null
+++ b/extensions/cookie/test/file_domain_hierarchy_inner_inner_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta3=tag3
diff --git a/extensions/cookie/test/file_domain_inner.html b/extensions/cookie/test/file_domain_inner.html
index 1a05c45f80..9db41e9040 100644
--- a/extensions/cookie/test/file_domain_inner.html
+++ b/extensions/cookie/test/file_domain_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta=tag">
   <script type="text/javascript">
     document.cookie = "can=has";
 
diff --git a/extensions/cookie/test/file_domain_inner.html^headers^ b/extensions/cookie/test/file_domain_inner.html^headers^
new file mode 100644
index 0000000000..993cedb908
--- /dev/null
+++ b/extensions/cookie/test/file_domain_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta=tag
diff --git a/extensions/cookie/test/file_domain_inner_inner.html b/extensions/cookie/test/file_domain_inner_inner.html
index 7bc0e44a98..5850e3fa0f 100644
--- a/extensions/cookie/test/file_domain_inner_inner.html
+++ b/extensions/cookie/test/file_domain_inner_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta2=tag2">
   <script type="text/javascript">
     document.cookie = "can2=has2";
 
diff --git a/extensions/cookie/test/file_domain_inner_inner.html^headers^ b/extensions/cookie/test/file_domain_inner_inner.html^headers^
new file mode 100644
index 0000000000..405494cd6e
--- /dev/null
+++ b/extensions/cookie/test/file_domain_inner_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta2=tag2
diff --git a/extensions/cookie/test/file_image_inner.html b/extensions/cookie/test/file_image_inner.html
index aada82d71a..902a055e4c 100644
--- a/extensions/cookie/test/file_image_inner.html
+++ b/extensions/cookie/test/file_image_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta=tag">
   <script type="text/javascript">
     document.cookie = "can=has";
 
diff --git a/extensions/cookie/test/file_image_inner.html^headers^ b/extensions/cookie/test/file_image_inner.html^headers^
new file mode 100644
index 0000000000..993cedb908
--- /dev/null
+++ b/extensions/cookie/test/file_image_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta=tag
diff --git a/extensions/cookie/test/file_image_inner_inner.html b/extensions/cookie/test/file_image_inner_inner.html
index 1989b53de7..d24ae0d27b 100644
--- a/extensions/cookie/test/file_image_inner_inner.html
+++ b/extensions/cookie/test/file_image_inner_inner.html
@@ -3,7 +3,6 @@
 <head>
   <link rel="stylesheet" type="text/css" media="all" href="http://example.org/tests/extensions/cookie/test/test1.css" />
   <link rel="stylesheet" type="text/css" media="all" href="http://example.com/tests/extensions/cookie/test/test2.css" />
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta2=tag2">
   <script type="text/javascript">
     function runTest() {
       document.cookie = "can2=has2";
diff --git a/extensions/cookie/test/file_image_inner_inner.html^headers^ b/extensions/cookie/test/file_image_inner_inner.html^headers^
new file mode 100644
index 0000000000..405494cd6e
--- /dev/null
+++ b/extensions/cookie/test/file_image_inner_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta2=tag2
diff --git a/extensions/cookie/test/file_loadflags_inner.html b/extensions/cookie/test/file_loadflags_inner.html
index 5a7a6ccc13..fbea01cfd3 100644
--- a/extensions/cookie/test/file_loadflags_inner.html
+++ b/extensions/cookie/test/file_loadflags_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta=tag">
   <script type="text/javascript">
     function runTest() {
       document.cookie = "can=has";
diff --git a/extensions/cookie/test/file_loadflags_inner.html^headers^ b/extensions/cookie/test/file_loadflags_inner.html^headers^
new file mode 100644
index 0000000000..993cedb908
--- /dev/null
+++ b/extensions/cookie/test/file_loadflags_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta=tag
diff --git a/extensions/cookie/test/file_localhost_inner.html b/extensions/cookie/test/file_localhost_inner.html
index db9917f000..82641d71c0 100644
--- a/extensions/cookie/test/file_localhost_inner.html
+++ b/extensions/cookie/test/file_localhost_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta=tag">
   <script type="text/javascript">
     document.cookie = "can=has";
 
diff --git a/extensions/cookie/test/file_localhost_inner.html^headers^ b/extensions/cookie/test/file_localhost_inner.html^headers^
new file mode 100644
index 0000000000..993cedb908
--- /dev/null
+++ b/extensions/cookie/test/file_localhost_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta=tag
diff --git a/extensions/cookie/test/file_loopback_inner.html b/extensions/cookie/test/file_loopback_inner.html
index e6c115c50b..9af1a65688 100644
--- a/extensions/cookie/test/file_loopback_inner.html
+++ b/extensions/cookie/test/file_loopback_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta=tag">
   <script type="text/javascript">
     document.cookie = "can=has";
 
diff --git a/extensions/cookie/test/file_loopback_inner.html^headers^ b/extensions/cookie/test/file_loopback_inner.html^headers^
new file mode 100644
index 0000000000..993cedb908
--- /dev/null
+++ b/extensions/cookie/test/file_loopback_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta=tag
diff --git a/extensions/cookie/test/file_subdomain_inner.html b/extensions/cookie/test/file_subdomain_inner.html
index 5f608b8110..0aab0d8525 100644
--- a/extensions/cookie/test/file_subdomain_inner.html
+++ b/extensions/cookie/test/file_subdomain_inner.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <META HTTP-EQUIV="Set-Cookie" CONTENT="meta=tag">
   <script type="text/javascript">
     document.cookie = "can=has";
 
diff --git a/extensions/cookie/test/file_subdomain_inner.html^headers^ b/extensions/cookie/test/file_subdomain_inner.html^headers^
new file mode 100644
index 0000000000..993cedb908
--- /dev/null
+++ b/extensions/cookie/test/file_subdomain_inner.html^headers^
@@ -0,0 +1 @@
+Set-Cookie: meta=tag
diff --git a/extensions/cookie/test/mochitest.ini b/extensions/cookie/test/mochitest.ini
index 673fad7b8d..66c7038e9f 100644
--- a/extensions/cookie/test/mochitest.ini
+++ b/extensions/cookie/test/mochitest.ini
@@ -6,16 +6,27 @@ support-files =
   damonbowling.jpg^headers^
   file_chromecommon.js
   file_domain_hierarchy_inner.html
+  file_domain_hierarchy_inner.html^headers^
   file_domain_hierarchy_inner_inner.html
+  file_domain_hierarchy_inner_inner.html^headers^
   file_domain_hierarchy_inner_inner_inner.html
+  file_domain_hierarchy_inner_inner_inner.html^headers^
   file_domain_inner.html
+  file_domain_inner.html^headers^
   file_domain_inner_inner.html
+  file_domain_inner_inner.html^headers^
   file_image_inner.html
+  file_image_inner.html^headers^
   file_image_inner_inner.html
+  file_image_inner_inner.html^headers^
   file_loadflags_inner.html
+  file_loadflags_inner.html^headers^
   file_localhost_inner.html
+  file_localhost_inner.html^headers^
   file_loopback_inner.html
+  file_loopback_inner.html^headers^
   file_subdomain_inner.html
+  file_subdomain_inner.html^headers^
   file_testcommon.js
   file_testloadflags.js
   file_testloadflags_chromescript.js
diff --git a/extensions/cookie/test/test_same_base_domain.html b/extensions/cookie/test/test_same_base_domain.html
index 9232b4e09b..acf020eb8e 100644
--- a/extensions/cookie/test/test_same_base_domain.html
+++ b/extensions/cookie/test/test_same_base_domain.html
@@ -5,7 +5,7 @@
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>        
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
 </head>
-<body onload="setupTest('http://test1.example.org/tests/extensions/cookie/test/file_domain_inner.html', 5, 2)">
+<body onload="setupTest('http://test1.example.org/tests/extensions/cookie/test/file_domain_inner.html', 4, 2)">
 <p id="display"></p>
 <pre id="test">
 <script class="testbody" type="text/javascript" src="file_testcommon.js">
diff --git a/extensions/cookie/test/test_same_base_domain_2.html b/extensions/cookie/test/test_same_base_domain_2.html
index d692524c5b..44e4008581 100644
--- a/extensions/cookie/test/test_same_base_domain_2.html
+++ b/extensions/cookie/test/test_same_base_domain_2.html
@@ -5,7 +5,7 @@
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>        
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
 </head>
-<body onload="setupTest('http://test1.example.org/tests/extensions/cookie/test/file_subdomain_inner.html', 5, 2)">
+<body onload="setupTest('http://test1.example.org/tests/extensions/cookie/test/file_subdomain_inner.html', 4, 2)">
 <p id="display"></p>
 <pre id="test">
 <script class="testbody" type="text/javascript" src="file_testcommon.js">
diff --git a/extensions/cookie/test/test_same_base_domain_3.html b/extensions/cookie/test/test_same_base_domain_3.html
index f0cd687f91..dfdbabde01 100644
--- a/extensions/cookie/test/test_same_base_domain_3.html
+++ b/extensions/cookie/test/test_same_base_domain_3.html
@@ -5,7 +5,7 @@
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>        
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
 </head>
-<body onload="setupTest('http://example.org/tests/extensions/cookie/test/file_subdomain_inner.html', 5, 2)">
+<body onload="setupTest('http://example.org/tests/extensions/cookie/test/file_subdomain_inner.html', 4, 2)">
 <p id="display"></p>
 <pre id="test">
 <script class="testbody" type="text/javascript" src="file_testcommon.js">
diff --git a/extensions/cookie/test/test_same_base_domain_5.html b/extensions/cookie/test/test_same_base_domain_5.html
index 49b2379b62..b603158c14 100644
--- a/extensions/cookie/test/test_same_base_domain_5.html
+++ b/extensions/cookie/test/test_same_base_domain_5.html
@@ -5,7 +5,7 @@
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>        
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
 </head>
-<body onload="setupTest('http://sub1.test1.example.org/tests/extensions/cookie/test/file_subdomain_inner.html', 5, 2)">
+<body onload="setupTest('http://sub1.test1.example.org/tests/extensions/cookie/test/file_subdomain_inner.html', 4, 2)">
 <p id="display"></p>
 <pre id="test">
 <script class="testbody" type="text/javascript" src="file_testcommon.js">
diff --git a/extensions/cookie/test/test_samedomain.html b/extensions/cookie/test/test_samedomain.html
index 9051d3b396..e8f623828b 100644
--- a/extensions/cookie/test/test_samedomain.html
+++ b/extensions/cookie/test/test_samedomain.html
@@ -5,7 +5,7 @@
   <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>        
   <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
 </head>
-<body onload="setupTest('http://example.org/tests/extensions/cookie/test/file_domain_inner.html', 5, 2)">
+<body onload="setupTest('http://example.org/tests/extensions/cookie/test/file_domain_inner.html', 4, 2)">
 <p id="display"></p>
 <pre id="test">
 <script class="testbody" type="text/javascript" src="file_testcommon.js">
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index f70a78c1cc..33652239cc 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -5207,6 +5207,9 @@ pref("intl.allow-insecure-text-input", false);
 // Enable meta-viewport support in remote APZ-enabled frames.
 pref("dom.meta-viewport.enabled", false);
 
+// Disable <meta http-equiv=set-cookie> support. See m-c bug 1457503 / UXP #1102.
+pref("dom.meta-set-cookie.enabled", false);
+
 // MozSettings debugging prefs for each component
 pref("dom.mozSettings.SettingsDB.debug.enabled", false);
 pref("dom.mozSettings.SettingsManager.debug.enabled", false);
