diff --git a/Tests/LibWeb/Text/expected/getComputedStyle-grid-template-rows-columns.txt b/Tests/LibWeb/Text/expected/getComputedStyle-grid-template-rows-columns.txt
new file mode 100644
index 0000000000..4e418b8e1f
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/getComputedStyle-grid-template-rows-columns.txt
@@ -0,0 +1,2 @@
+  100px 100px
+50px 50px
diff --git a/Tests/LibWeb/Text/input/getComputedStyle-grid-template-rows-columns.html b/Tests/LibWeb/Text/input/getComputedStyle-grid-template-rows-columns.html
new file mode 100644
index 0000000000..b75e03aa34
--- /dev/null
+++ b/Tests/LibWeb/Text/input/getComputedStyle-grid-template-rows-columns.html
@@ -0,0 +1,21 @@
+<script src="include.js"></script>
+<style>
+    .grid-container {
+        width: 200px;
+        display: grid;
+        background-color: lightsalmon;
+    }
+
+    .grid-item {
+        height: 50px;
+        background-color: lightblue;
+    }
+</style>
+<div class="grid-container" style="grid-template-columns: auto auto"><div class="grid-item"></div><div class="grid-item"></div><div class="grid-item"></div><div class="grid-item"></div></div>
+<script>
+    test(() => {
+        const grid = document.querySelector(".grid-container");
+        println(getComputedStyle(grid).gridTemplateColumns);
+        println(getComputedStyle(grid).gridTemplateRows);
+    });
+</script>
diff --git a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
index c5abdca7ce..af68458823 100644
--- a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
+++ b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
@@ -250,6 +250,16 @@ RefPtr<CSSStyleValue const> ResolvedCSSStyleDeclaration::style_value_for_propert
         return style_value_for_shadow(layout_node.computed_values().box_shadow());
     case PropertyID::Color:
         return CSSColorValue::create_from_color(layout_node.computed_values().color());
+    // For grid-template-columns and grid-template-rows the resolved value is the used value.
+    // https://www.w3.org/TR/css-grid-2/#resolved-track-list-standalone
+    case PropertyID::GridTemplateColumns: {
+        auto const& paintable_box = verify_cast<Painting::PaintableBox const>(*layout_node.paintable());
+        return paintable_box.used_values_for_grid_template_columns();
+    }
+    case PropertyID::GridTemplateRows: {
+        auto const& paintable_box = verify_cast<Painting::PaintableBox const>(*layout_node.paintable());
+        return paintable_box.used_values_for_grid_template_rows();
+    }
     case PropertyID::OutlineColor:
         return CSSColorValue::create_from_color(layout_node.computed_values().outline_color());
     case PropertyID::TextDecorationColor:
diff --git a/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp b/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
index b55efa2ef4..5c475a930b 100644
--- a/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
+++ b/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
@@ -1873,6 +1873,23 @@ void GridFormattingContext::run(Box const&, LayoutMode, AvailableSpace const& av
         if (auto independent_formatting_context = layout_inside(grid_item.box, LayoutMode::Normal, available_space_for_children))
             independent_formatting_context->parent_context_did_dimension_child_root_box();
     }
+
+    Vector<Variant<CSS::ExplicitGridTrack, CSS::GridLineNames>> grid_track_columns;
+    grid_track_columns.ensure_capacity(m_grid_columns.size());
+    for (auto const& column : m_grid_columns) {
+        grid_track_columns.append(CSS::ExplicitGridTrack { CSS::GridSize { CSS::LengthPercentage(CSS::Length::make_px(column.base_size)) } });
+    }
+
+    Vector<Variant<CSS::ExplicitGridTrack, CSS::GridLineNames>> grid_track_rows;
+    grid_track_rows.ensure_capacity(m_grid_rows.size());
+    for (auto const& row : m_grid_rows) {
+        grid_track_rows.append(CSS::ExplicitGridTrack { CSS::GridSize { CSS::LengthPercentage(CSS::Length::make_px(row.base_size)) } });
+    }
+
+    // getComputedStyle() needs to return the resolved values of grid-template-columns and grid-template-rows
+    // so they need to be saved in the state, and then assigned to paintables in LayoutState::commit()
+    m_state.get_mutable(grid_container()).set_grid_template_columns(CSS::GridTrackSizeListStyleValue::create(move(grid_track_columns)));
+    m_state.get_mutable(grid_container()).set_grid_template_rows(CSS::GridTrackSizeListStyleValue::create(move(grid_track_rows)));
 }
 
 void GridFormattingContext::layout_absolutely_positioned_element(Box const& box, AvailableSpace const& available_space)
diff --git a/Userland/Libraries/LibWeb/Layout/LayoutState.cpp b/Userland/Libraries/LibWeb/Layout/LayoutState.cpp
index 9f55d639aa..5cea70823e 100644
--- a/Userland/Libraries/LibWeb/Layout/LayoutState.cpp
+++ b/Userland/Libraries/LibWeb/Layout/LayoutState.cpp
@@ -278,6 +278,11 @@ void LayoutState::commit(Box& root)
                 auto& svg_geometry_paintable = static_cast<Painting::SVGPathPaintable&>(paintable_box);
                 svg_geometry_paintable.set_computed_path(move(*used_values.computed_svg_path()));
             }
+
+            if (node.display().is_grid_inside()) {
+                paintable_box.set_used_values_for_grid_template_columns(used_values.grid_template_columns());
+                paintable_box.set_used_values_for_grid_template_rows(used_values.grid_template_rows());
+            }
         }
     }
 
diff --git a/Userland/Libraries/LibWeb/Layout/LayoutState.h b/Userland/Libraries/LibWeb/Layout/LayoutState.h
index fe0f0fcfb0..0bab0f50ef 100644
--- a/Userland/Libraries/LibWeb/Layout/LayoutState.h
+++ b/Userland/Libraries/LibWeb/Layout/LayoutState.h
@@ -139,6 +139,12 @@ struct LayoutState {
         void set_computed_svg_transforms(Painting::SVGGraphicsPaintable::ComputedTransforms const& computed_transforms) { m_computed_svg_transforms = computed_transforms; }
         auto const& computed_svg_transforms() const { return m_computed_svg_transforms; }
 
+        void set_grid_template_columns(RefPtr<CSS::GridTrackSizeListStyleValue> used_values_for_grid_template_columns) { m_grid_template_columns = move(used_values_for_grid_template_columns); }
+        auto const& grid_template_columns() const { return m_grid_template_columns; }
+
+        void set_grid_template_rows(RefPtr<CSS::GridTrackSizeListStyleValue> used_values_for_grid_template_rows) { m_grid_template_rows = move(used_values_for_grid_template_rows); }
+        auto const& grid_template_rows() const { return m_grid_template_rows; }
+
     private:
         AvailableSize available_width_inside() const;
         AvailableSize available_height_inside() const;
@@ -166,6 +172,9 @@ struct LayoutState {
 
         Optional<Gfx::Path> m_computed_svg_path;
         Optional<Painting::SVGGraphicsPaintable::ComputedTransforms> m_computed_svg_transforms;
+
+        RefPtr<CSS::GridTrackSizeListStyleValue> m_grid_template_columns;
+        RefPtr<CSS::GridTrackSizeListStyleValue> m_grid_template_rows;
     };
 
     // Commits the used values produced by layout and builds a paintable tree.
diff --git a/Userland/Libraries/LibWeb/Painting/PaintableBox.h b/Userland/Libraries/LibWeb/Painting/PaintableBox.h
index 973d69f38c..448528cbeb 100644
--- a/Userland/Libraries/LibWeb/Painting/PaintableBox.h
+++ b/Userland/Libraries/LibWeb/Painting/PaintableBox.h
@@ -6,6 +6,7 @@
 
 #pragma once
 
+#include <LibWeb/CSS/StyleValues/GridTrackSizeListStyleValue.h>
 #include <LibWeb/Painting/BackgroundPainting.h>
 #include <LibWeb/Painting/BorderPainting.h>
 #include <LibWeb/Painting/BorderRadiusCornerClipper.h>
@@ -227,6 +228,12 @@ public:
 
     [[nodiscard]] bool is_scrollable() const;
 
+    void set_used_values_for_grid_template_columns(RefPtr<CSS::GridTrackSizeListStyleValue> style_value) { m_used_values_for_grid_template_columns = move(style_value); }
+    RefPtr<CSS::GridTrackSizeListStyleValue> const& used_values_for_grid_template_columns() const { return m_used_values_for_grid_template_columns; }
+
+    void set_used_values_for_grid_template_rows(RefPtr<CSS::GridTrackSizeListStyleValue> style_value) { m_used_values_for_grid_template_rows = move(style_value); }
+    RefPtr<CSS::GridTrackSizeListStyleValue> const& used_values_for_grid_template_rows() const { return m_used_values_for_grid_template_rows; }
+
 protected:
     explicit PaintableBox(Layout::Box const&);
 
@@ -287,6 +294,9 @@ private:
     ResolvedBackground m_resolved_background;
 
     OwnPtr<StickyInsets> m_sticky_insets;
+
+    RefPtr<CSS::GridTrackSizeListStyleValue> m_used_values_for_grid_template_columns;
+    RefPtr<CSS::GridTrackSizeListStyleValue> m_used_values_for_grid_template_rows;
 };
 
 class PaintableWithLines : public PaintableBox {