diff --git a/components/style/properties/data.py b/components/style/properties/data.py
index 46cb724e11d..b8568292d28 100644
--- a/components/style/properties/data.py
+++ b/components/style/properties/data.py
@@ -653,7 +653,6 @@ def _remove_common_first_line_and_first_letter_properties(props, engine):
         props.remove("text-emphasis-style")
         props.remove("text-emphasis-color")
         props.remove("text-decoration-skip-ink")
-        props.remove("text-decoration-thickness")
         props.remove("text-underline-offset")
 
     props.remove("overflow-wrap")
diff --git a/components/style/properties/longhands/text.mako.rs b/components/style/properties/longhands/text.mako.rs
index a592e2f1290..9f0d3f38213 100644
--- a/components/style/properties/longhands/text.mako.rs
+++ b/components/style/properties/longhands/text.mako.rs
@@ -74,6 +74,7 @@ ${helpers.predefined_type(
    "LengthOrAuto",
    "computed::LengthOrAuto::auto()",
    engines="gecko",
+   initial_specified_value="specified::LengthOrAuto::auto()",
    animation_value_type="ComputedValue",
    gecko_pref="layout.css.text-decoration-thickness.enabled",
    spec="https://drafts.csswg.org/css-text-decor-4/#text-decoration-width-property"
diff --git a/components/style/properties/shorthands/text.mako.rs b/components/style/properties/shorthands/text.mako.rs
index 905512b08df..994d31c18b2 100644
--- a/components/style/properties/shorthands/text.mako.rs
+++ b/components/style/properties/shorthands/text.mako.rs
@@ -8,12 +8,13 @@
                     engines="gecko servo-2013"
                     flags="SHORTHAND_IN_GETCS"
                     sub_properties="text-decoration-line
-                    ${' text-decoration-style text-decoration-color' if engine == 'gecko' else ''}"
+                    ${' text-decoration-style text-decoration-color text-decoration-thickness' if engine == 'gecko' else ''}"
                     spec="https://drafts.csswg.org/css-text-decor/#propdef-text-decoration">
 
     % if engine == "gecko":
         use crate::values::specified;
-        use crate::properties::longhands::{text_decoration_style, text_decoration_color};
+        use crate::properties::longhands::{text_decoration_style, text_decoration_color, text_decoration_thickness};
+        use crate::properties::{PropertyId, LonghandId};
     % endif
     use crate::properties::longhands::text_decoration_line;
 
@@ -22,11 +23,14 @@
         input: &mut Parser<'i, 't>,
     ) -> Result<Longhands, ParseError<'i>> {
         % if engine == "gecko":
-            let (mut line, mut style, mut color, mut any) = (None, None, None, false);
+            let (mut line, mut style, mut color, mut thickness, mut any) = (None, None, None, None, false);
         % else:
             let (mut line, mut any) = (None, false);
         % endif
 
+        let text_decoration_thickness_enabled =
+            PropertyId::Longhand(LonghandId::TextDecorationThickness).enabled_for_all_content();
+
         loop {
             macro_rules! parse_component {
                 ($value:ident, $module:ident) => (
@@ -45,6 +49,9 @@
             % if engine == "gecko":
                 parse_component!(style, text_decoration_style);
                 parse_component!(color, text_decoration_color);
+                if text_decoration_thickness_enabled {
+                    parse_component!(thickness, text_decoration_thickness);
+                }
             % endif
 
             break;
@@ -60,6 +67,7 @@
             % if engine == "gecko":
                 text_decoration_style: unwrap_or_initial!(text_decoration_style, style),
                 text_decoration_color: unwrap_or_initial!(text_decoration_color, color),
+                text_decoration_thickness: unwrap_or_initial!(text_decoration_thickness, thickness),
             % endif
         })
     }
@@ -78,6 +86,13 @@
                     dest.write_str(" ")?;
                     self.text_decoration_color.to_css(dest)?;
                 }
+
+                if let Some(text_decoration_thickness) = self.text_decoration_thickness {
+                    if !text_decoration_thickness.is_auto() {
+                        dest.write_str(" ")?;
+                        self.text_decoration_thickness.to_css(dest)?;
+                    }
+                }
             % endif
 
             Ok(())