diff --git a/components/style/properties/gecko.mako.rs b/components/style/properties/gecko.mako.rs
index a88aec3b684..0e9b178944c 100644
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@@ -799,11 +799,8 @@ fn static_assert() {
     ${impl_simple_type_with_conversion("masonry_auto_flow", "mMasonryAutoFlow")}
 </%self:impl_trait>
 
-<% skip_outline_longhands = " ".join("outline-style outline-width".split() +
-                                     ["-moz-outline-radius-{0}".format(x.replace("_", ""))
-                                      for x in CORNERS]) %>
 <%self:impl_trait style_struct_name="Outline"
-                  skip_longhands="${skip_outline_longhands}">
+                  skip_longhands="outline-style outline-width">
 
     pub fn set_outline_style(&mut self, v: longhands::outline_style::computed_value::T) {
         self.gecko.mOutlineStyle = v;
@@ -831,12 +828,6 @@ fn static_assert() {
                                 inherit_from="mOutlineWidth",
                                 round_to_pixels=True) %>
 
-    % for corner in CORNERS:
-    <% impl_corner_style_coord("_moz_outline_radius_%s" % corner.replace("_", ""),
-                               "mOutlineRadius",
-                               corner) %>
-    % endfor
-
     pub fn outline_has_nonzero_width(&self) -> bool {
         self.gecko.mActualOutlineWidth != 0
     }
diff --git a/components/style/properties/longhands/outline.mako.rs b/components/style/properties/longhands/outline.mako.rs
index e5cd09fbe82..c744f5f523f 100644
--- a/components/style/properties/longhands/outline.mako.rs
+++ b/components/style/properties/longhands/outline.mako.rs
@@ -42,20 +42,6 @@ ${helpers.predefined_type(
     spec="https://drafts.csswg.org/css-ui/#propdef-outline-width",
 )}
 
-// The -moz-outline-radius-* properties are non-standard and not on a standards track.
-% for corner in ["topleft", "topright", "bottomright", "bottomleft"]:
-    ${helpers.predefined_type(
-        "-moz-outline-radius-" + corner,
-        "BorderCornerRadius",
-        "computed::BorderCornerRadius::zero()",
-        engines="gecko",
-        boxed=True,
-        animation_value_type="BorderCornerRadius",
-        gecko_pref="layout.css.moz-outline-radius.enabled",
-        spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-outline-radius)",
-    )}
-% endfor
-
 ${helpers.predefined_type(
     "outline-offset",
     "Length",
diff --git a/components/style/properties/shorthands/outline.mako.rs b/components/style/properties/shorthands/outline.mako.rs
index db397498919..b90f8d966f3 100644
--- a/components/style/properties/shorthands/outline.mako.rs
+++ b/components/style/properties/shorthands/outline.mako.rs
@@ -78,50 +78,3 @@
         }
     }
 </%helpers:shorthand>
-
-// The -moz-outline-radius shorthand is non-standard and not on a standards track.
-<%helpers:shorthand
-    name="-moz-outline-radius"
-    engines="gecko"
-    gecko_pref="layout.css.moz-outline-radius.enabled"
-    sub_properties="${' '.join(
-        '-moz-outline-radius-%s' % corner
-        for corner in ['topleft', 'topright', 'bottomright', 'bottomleft']
-    )}"
-    spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-outline-radius)"
->
-    use crate::values::generics::rect::Rect;
-    use crate::values::specified::border::BorderRadius;
-    use crate::parser::Parse;
-
-    pub fn parse_value<'i, 't>(
-        context: &ParserContext,
-        input: &mut Parser<'i, 't>,
-    ) -> Result<Longhands, ParseError<'i>> {
-        let radii = BorderRadius::parse(context, input)?;
-        Ok(expanded! {
-            _moz_outline_radius_topleft: radii.top_left,
-            _moz_outline_radius_topright: radii.top_right,
-            _moz_outline_radius_bottomright: radii.bottom_right,
-            _moz_outline_radius_bottomleft: radii.bottom_left,
-        })
-    }
-
-    impl<'a> ToCss for LonghandsToSerialize<'a>  {
-        fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result where W: fmt::Write {
-            use crate::values::generics::border::BorderCornerRadius;
-
-            let LonghandsToSerialize {
-                _moz_outline_radius_topleft: &BorderCornerRadius(ref tl),
-                _moz_outline_radius_topright: &BorderCornerRadius(ref tr),
-                _moz_outline_radius_bottomright: &BorderCornerRadius(ref br),
-                _moz_outline_radius_bottomleft: &BorderCornerRadius(ref bl),
-            } = *self;
-
-            let widths = Rect::new(tl.width(), tr.width(), br.width(), bl.width());
-            let heights = Rect::new(tl.height(), tr.height(), br.height(), bl.height());
-
-            BorderRadius::serialize_rects(widths, heights, dest)
-        }
-    }
-</%helpers:shorthand>
diff --git a/components/style/values/generics/border.rs b/components/style/values/generics/border.rs
index 37d91464b01..e4e78e31222 100644
--- a/components/style/values/generics/border.rs
+++ b/components/style/values/generics/border.rs
@@ -147,7 +147,7 @@ impl<L> BorderSpacing<L> {
     }
 }
 
-/// A generic value for `border-radius`, `outline-radius` and `inset()`.
+/// A generic value for `border-radius` and `inset()`.
 ///
 /// <https://drafts.csswg.org/css-backgrounds-3/#border-radius>
 #[derive(