diff --git a/Tests/LibWeb/Layout/expected/getComputedStyle-on-unconnected-element.txt b/Tests/LibWeb/Layout/expected/getComputedStyle-on-unconnected-element.txt
new file mode 100644
index 0000000000..08865062d8
--- /dev/null
+++ b/Tests/LibWeb/Layout/expected/getComputedStyle-on-unconnected-element.txt
@@ -0,0 +1,7 @@
+Viewport <#document> at (0,0) content-size 800x600 children: not-inline
+ BlockContainer at (0,0) content-size 800x37.835937 [BFC] children: not-inline
+ BlockContainer at (8,8) content-size 784x21.835937 children: inline
+ line 0 width: 362.617187, height: 21.835937, bottom: 21.835937, baseline: 16.914062
+ frag 0 from TextNode start: 0, length: 35, rect: [8,8 362.617187x21.835937]
+ "This test passes if we don't crash."
+ TextNode <#text>
diff --git a/Tests/LibWeb/Layout/input/getComputedStyle-on-unconnected-element.html b/Tests/LibWeb/Layout/input/getComputedStyle-on-unconnected-element.html
new file mode 100644
index 0000000000..34c51bfef6
--- /dev/null
+++ b/Tests/LibWeb/Layout/input/getComputedStyle-on-unconnected-element.html
@@ -0,0 +1,11 @@
+
+This test passes if we don't crash.
\ No newline at end of file
diff --git a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
index c1cc9fc703..99a2987d8d 100644
--- a/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
+++ b/Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp
@@ -666,6 +666,11 @@ ErrorOr> ResolvedCSSStyleDeclaration::style_value_for_p
Optional ResolvedCSSStyleDeclaration::property(PropertyID property_id) const
{
+ // https://www.w3.org/TR/cssom-1/#dom-window-getcomputedstyle
+ // NOTE: This is a partial enforcement of step 5 ("If elt is connected, ...")
+ if (!m_element->is_connected())
+ return {};
+
if (CSS::property_affects_layout(property_id)) {
const_cast(m_element->document()).update_layout();
} else {