diff --git a/components/style/properties/helpers.mako.rs b/components/style/properties/helpers.mako.rs
index 6563b97df15..478e1be659b 100644
--- a/components/style/properties/helpers.mako.rs
+++ b/components/style/properties/helpers.mako.rs
@@ -809,7 +809,8 @@
     % endif
 </%def>
 
-<%def name="four_sides_shorthand(name, sub_property_pattern, parser_function, needs_context=True, **kwargs)">
+<%def name="four_sides_shorthand(name, sub_property_pattern, parser_function,
+                                 needs_context=True, allow_quirks=False, **kwargs)">
     <% sub_properties=' '.join(sub_property_pattern % side for side in ['top', 'right', 'bottom', 'left']) %>
     <%call expr="self.shorthand(name, sub_properties=sub_properties, **kwargs)">
         #[allow(unused_imports)]
@@ -819,7 +820,9 @@
 
         pub fn parse_value(context: &ParserContext, input: &mut Parser) -> Result<Longhands, ()> {
             let (top, right, bottom, left) =
-            % if needs_context:
+            % if allow_quirks:
+                try!(parse_four_sides(input, |i| ${parser_function}_quirky(context, i, specified::AllowQuirks::Yes)));
+            % elif needs_context:
                 try!(parse_four_sides(input, |i| ${parser_function}(context, i)));
             % else:
                 try!(parse_four_sides(input, ${parser_function}));
diff --git a/components/style/properties/shorthand/margin.mako.rs b/components/style/properties/shorthand/margin.mako.rs
index 4dcaa71e626..07b6ba6bbed 100644
--- a/components/style/properties/shorthand/margin.mako.rs
+++ b/components/style/properties/shorthand/margin.mako.rs
@@ -6,4 +6,5 @@
 
 ${helpers.four_sides_shorthand("margin", "margin-%s", "specified::LengthOrPercentageOrAuto::parse",
                                spec="https://drafts.csswg.org/css-box/#propdef-margin",
-                               allowed_in_page_rule=True)}
+                               allowed_in_page_rule=True,
+                               allow_quirks=True)}
diff --git a/tests/wpt/metadata/quirks-mode/unitless-length.html.ini b/tests/wpt/metadata/quirks-mode/unitless-length.html.ini
index 3a7420644f1..57b312ab152 100644
--- a/tests/wpt/metadata/quirks-mode/unitless-length.html.ini
+++ b/tests/wpt/metadata/quirks-mode/unitless-length.html.ini
@@ -12,9 +12,6 @@
     expected:
       if os == "mac": FAIL
 
-  [margin: 1 (quirks)]
-    expected: FAIL
-
   [max-height: 1 (quirks)]
     expected: FAIL
 
@@ -75,9 +72,6 @@
     expected:
       if os == "mac": FAIL
 
-  [margin: +1 (quirks)]
-    expected: FAIL
-
   [max-height: +1 (quirks)]
     expected: FAIL
 
@@ -138,9 +132,6 @@
     expected:
       if os == "mac": FAIL
 
-  [margin: -1 (quirks)]
-    expected: FAIL
-
   [padding: -1 (quirks)]
     expected: FAIL
 
@@ -177,9 +168,6 @@
     expected:
       if os == "mac": FAIL
 
-  [margin: 1.5 (quirks)]
-    expected: FAIL
-
   [max-height: 1.5 (quirks)]
     expected: FAIL
 
@@ -240,9 +228,6 @@
     expected:
       if os == "mac": FAIL
 
-  [margin: +1.5 (quirks)]
-    expected: FAIL
-
   [max-height: +1.5 (quirks)]
     expected: FAIL
 
@@ -303,9 +288,6 @@
     expected:
       if os == "mac": FAIL
 
-  [margin: -1.5 (quirks)]
-    expected: FAIL
-
   [padding: -1.5 (quirks)]
     expected: FAIL
 
@@ -1314,27 +1296,15 @@
     expected:
       if os == "mac": FAIL
 
-  [margin: 1px 2 (quirks)]
-    expected: FAIL
-
   [padding: 1px 2 (quirks)]
     expected: FAIL
 
-  [margin: 1 2px (quirks)]
-    expected: FAIL
-
   [padding: 1 2px (quirks)]
     expected: FAIL
 
-  [margin: 1 +2 (quirks)]
-    expected: FAIL
-
   [padding: 1 +2 (quirks)]
     expected: FAIL
 
-  [margin: 1 -2 (quirks)]
-    expected: FAIL
-
   [padding: 1 -2 (quirks)]
     expected: FAIL