diff --git a/Libraries/LibWeb/Editing/Commands.cpp b/Libraries/LibWeb/Editing/Commands.cpp
index 7f744f77d77..5592019192f 100644
--- a/Libraries/LibWeb/Editing/Commands.cpp
+++ b/Libraries/LibWeb/Editing/Commands.cpp
@@ -2228,6 +2228,33 @@ bool command_remove_format_action(DOM::Document& document, String const&)
     return true;
 }
 
+// https://w3c.github.io/editing/docs/execCommand/#the-selectall-command
+bool command_select_all_action(DOM::Document& document, String const&)
+{
+    // NOTE: The spec mentions "This is totally broken". So fair warning :^)
+
+    // 1. Let target be the body element of the context object.
+    GC::Ptr<DOM::Node> target = document.body();
+
+    // 2. If target is null, let target be the context object's documentElement.
+    if (!target)
+        target = document.document_element();
+
+    // 3. If target is null, call getSelection() on the context object, and call removeAllRanges() on the result.
+    auto& selection = *document.get_selection();
+    if (!target) {
+        selection.remove_all_ranges();
+    }
+
+    // 4. Otherwise, call getSelection() on the context object, and call selectAllChildren(target) on the result.
+    else {
+        MUST(selection.select_all_children(*target));
+    }
+
+    // 5. Return true.
+    return true;
+}
+
 // https://w3c.github.io/editing/docs/execCommand/#the-strikethrough-command
 bool command_strikethrough_action(DOM::Document& document, String const&)
 {
@@ -2602,6 +2629,11 @@ static Array const commands {
         .command = CommandNames::removeFormat,
         .action = command_remove_format_action,
     },
+    // https://w3c.github.io/editing/docs/execCommand/#the-selectall-command
+    CommandDefinition {
+        .command = CommandNames::selectAll,
+        .action = command_select_all_action,
+    },
     // https://w3c.github.io/editing/docs/execCommand/#the-strikethrough-command
     CommandDefinition {
         .command = CommandNames::strikethrough,
diff --git a/Libraries/LibWeb/Editing/Commands.h b/Libraries/LibWeb/Editing/Commands.h
index eb9ca1c695a..611b3eb781a 100644
--- a/Libraries/LibWeb/Editing/Commands.h
+++ b/Libraries/LibWeb/Editing/Commands.h
@@ -75,6 +75,7 @@ bool command_justify_right_state(DOM::Document const&);
 String command_justify_right_value(DOM::Document const&);
 bool command_outdent_action(DOM::Document&, String const&);
 bool command_remove_format_action(DOM::Document&, String const&);
+bool command_select_all_action(DOM::Document&, String const&);
 bool command_strikethrough_action(DOM::Document&, String const&);
 bool command_style_with_css_action(DOM::Document&, String const&);
 bool command_style_with_css_state(DOM::Document const&);
diff --git a/Tests/LibWeb/Text/expected/Editing/execCommand-selectAll.txt b/Tests/LibWeb/Text/expected/Editing/execCommand-selectAll.txt
new file mode 100644
index 00000000000..aa14bdf2a2c
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/Editing/execCommand-selectAll.txt
@@ -0,0 +1,3 @@
+No range.
+DIV 0 - DIV 0
+BODY 0 - BODY 5
diff --git a/Tests/LibWeb/Text/input/Editing/execCommand-selectAll.html b/Tests/LibWeb/Text/input/Editing/execCommand-selectAll.html
new file mode 100644
index 00000000000..15c278e9fa4
--- /dev/null
+++ b/Tests/LibWeb/Text/input/Editing/execCommand-selectAll.html
@@ -0,0 +1,37 @@
+<script src="../include.js"></script>
+<div contenteditable="true">
+    <span>foobar</span>
+    <ul>
+        <li>foo</li>
+        <li>bar</li>
+        <li>baz</li>
+    </ul>
+</div>
+<script>
+    test(() => {
+        const selection = getSelection();
+
+        const reportSelection = () => {
+            if (selection.rangeCount === 0) {
+                println('No range.');
+                return;
+            }
+            const range = selection.getRangeAt(0);
+            println(`${range.startContainer.nodeName} ${range.startOffset} - ${range.endContainer.nodeName} ${range.endOffset}`);
+        };
+
+        reportSelection();
+
+        let divElm = document.querySelector('div');
+        let range = document.createRange();
+        range.setStart(divElm, 0);
+        range.setEnd(divElm, 0);
+        selection.addRange(range);
+
+        reportSelection();
+
+        // Perform selectAll
+        document.execCommand('selectAll');
+        reportSelection();
+    });
+</script>