diff --git a/components/style/properties/longhand/box.mako.rs b/components/style/properties/longhand/box.mako.rs
index a88db8bf03e..69ad8440148 100644
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 <%namespace name="helpers" file="/helpers.mako.rs" />
-<% from data import Method, to_rust_ident %>
+<% from data import Keyword, Method, to_rust_ident %>
 
 <% data.new_style_struct("Box",
                          inherited=False,
@@ -126,8 +126,12 @@ ${helpers.single_keyword("clear", "none left right both", gecko_ffi_name="mBreak
   use cssparser::ToCss;
   use std::fmt;
 
-  <% vertical_align_keywords = (
-      "baseline sub super top text-top middle bottom text-bottom".split()) %>
+  <% vertical_align = data.longhands_by_name["vertical-align"] %>
+  <% vertical_align.keyword = Keyword("vertical-align",
+                                      "baseline sub super top text-top middle bottom text-bottom",
+                                      extra_gecko_values="middle-with-baseline") %>
+  <% vertical_align_keywords = vertical_align.keyword.values_for(product) %>
+
   #[allow(non_camel_case_types)]
   #[derive(Debug, Clone, PartialEq, Copy, HeapSizeOf)]
   pub enum SpecifiedValue {
diff --git a/ports/geckolib/properties.mako.rs b/ports/geckolib/properties.mako.rs
index 75ef9c6215c..d9fec02b3b1 100644
--- a/ports/geckolib/properties.mako.rs
+++ b/ports/geckolib/properties.mako.rs
@@ -625,7 +625,7 @@ fn static_assert() {
 
 </%self:impl_trait>
 
-<%self:impl_trait style_struct_name="Box" skip_longhands="display overflow-y">
+<%self:impl_trait style_struct_name="Box" skip_longhands="display overflow-y vertical-align">
 
     // We manually-implement the |display| property until we get general
     // infrastructure for preffing certain values.
@@ -659,6 +659,23 @@ fn static_assert() {
         }
     }
 
+    fn set_vertical_align(&mut self, v: longhands::vertical_align::computed_value::T) {
+        <% keyword = data.longhands_by_name["vertical-align"].keyword %>
+        use style::properties::longhands::vertical_align::computed_value::T;
+        // FIXME: Align binary representations and ditch |match| for cast + static_asserts
+        match v {
+            % for value in keyword.values_for('gecko'):
+                T::${to_rust_ident(value)} =>
+                    self.gecko.mVerticalAlign.set_int(structs::${keyword.gecko_constant(value)} as i32),
+            % endfor
+            T::LengthOrPercentage(v) => self.gecko.mVerticalAlign.set(v),
+        }
+    }
+    fn copy_vertical_align_from(&mut self, other: &Self) {
+        self.gecko.mVerticalAlign.mUnit = other.gecko.mVerticalAlign.mUnit;
+        self.gecko.mVerticalAlign.mValue = other.gecko.mVerticalAlign.mValue;
+    }
+
 </%self:impl_trait>
 
 <%self:impl_trait style_struct_name="Background" skip_longhands="background-color" skip_additionals="*">