diff --git a/components/script/dom/webidls/CSSStyleDeclaration.webidl b/components/script/dom/webidls/CSSStyleDeclaration.webidl
index f13bcfa4048..62baec54423 100644
--- a/components/script/dom/webidls/CSSStyleDeclaration.webidl
+++ b/components/script/dom/webidls/CSSStyleDeclaration.webidl
@@ -332,4 +332,6 @@ partial interface CSSStyleDeclaration {
   [SetterThrows, TreatNullAs=EmptyString] attribute DOMString animationName;
   [SetterThrows, TreatNullAs=EmptyString] attribute DOMString animation-duration;
   [SetterThrows, TreatNullAs=EmptyString] attribute DOMString animationDuration;
+  [SetterThrows, TreatNullAs=EmptyString] attribute DOMString animation-timing-function;
+  [SetterThrows, TreatNullAs=EmptyString] attribute DOMString animationTimingFunction;
 };
diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhand/box.mako.rs
index 898a1902548..3a61b987eeb 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@@ -880,6 +880,12 @@ ${helpers.single_keyword("overflow-x", "visible hidden scroll auto", need_clone=
     pub use super::transition_duration::SpecifiedValue;
 </%helpers:longhand>
 
+<%helpers:longhand name="animation-timing-function" experimental="True">
+    pub use super::transition_timing_function::computed_value;
+    pub use super::transition_timing_function::{parse, get_initial_value};
+    pub use super::transition_timing_function::SpecifiedValue;
+</%helpers:longhand>
+
 // CSSOM View Module
 // https://www.w3.org/TR/cssom-view-1/
 ${helpers.single_keyword("scroll-behavior",