diff --git a/docs/components/radio-group.md b/docs/components/radio-group.md
index d5a28963d..b58d23072 100644
--- a/docs/components/radio-group.md
+++ b/docs/components/radio-group.md
@@ -5,10 +5,10 @@
 Radio groups are used to group multiple [radios](/components/radio) or [radio buttons](/components/radio-button) so they function as a single form control.
 
 ```html preview
-<sl-radio-group label="Select an option">
-  <sl-radio name="option" value="1" checked>Option 1</sl-radio>
-  <sl-radio name="option" value="2">Option 2</sl-radio>
-  <sl-radio name="option" value="3">Option 3</sl-radio>
+<sl-radio-group label="Select an option" value="1">
+  <sl-radio value="1">Option 1</sl-radio>
+  <sl-radio value="2">Option 2</sl-radio>
+  <sl-radio value="3">Option 3</sl-radio>
 </sl-radio-group>
 ```
 
@@ -16,16 +16,10 @@ Radio groups are used to group multiple [radios](/components/radio) or [radio bu
 import { SlRadio, SlRadioGroup } from '@shoelace-style/shoelace/dist/react';
 
 const App = () => (
-  <SlRadioGroup label="Select an option">
-    <SlRadio name="option" value="1" checked>
-      Option 1
-    </SlRadio>
-    <SlRadio name="option" value="2">
-      Option 2
-    </SlRadio>
-    <SlRadio name="option" value="3">
-      Option 3
-    </SlRadio>
+  <SlRadioGroup label="Select an option" value="1">
+    <SlRadio value="1">Option 1</SlRadio>
+    <SlRadio value="2">Option 2</SlRadio>
+    <SlRadio value="3">Option 3</SlRadio>
   </SlRadioGroup>
 );
 ```
@@ -37,8 +31,8 @@ const App = () => (
 You can show the fieldset and legend that wraps the radio group using the `fieldset` attribute. If you don't use this option, you should still provide a label so screen readers announce the control correctly.
 
 ```html preview
-<sl-radio-group label="Select an option" fieldset>
-  <sl-radio name="option" value="1" checked>Option 1</sl-radio>
+<sl-radio-group label="Select an option" value="1" fieldset>
+  <sl-radio name="option" value="1">Option 1</sl-radio>
   <sl-radio name="option" value="2">Option 2</sl-radio>
   <sl-radio name="option" value="3">Option 3</sl-radio>
 </sl-radio-group>
@@ -48,8 +42,8 @@ You can show the fieldset and legend that wraps the radio group using the `field
 import { SlRadio, SlRadioGroup } from '@shoelace-style/shoelace/dist/react';
 
 const App = () => (
-  <SlRadioGroup label="Select an option" fieldset>
-    <SlRadio name="option" value="1" checked>
+  <SlRadioGroup label="Select an option" value="1" fieldset>
+    <SlRadio name="option" value="1">
       Option 1
     </SlRadio>
     <SlRadio name="option" value="2">
@@ -67,8 +61,8 @@ const App = () => (
 [Radio buttons](/components/radio-button) offer an alternate way to display radio controls. In this case, an internal [button group](/components/button-group) is used to group the buttons into a single, cohesive control.
 
 ```html preview
-<sl-radio-group label="Select an option">
-  <sl-radio-button name="option" value="1" checked>Option 1</sl-radio-button>
+<sl-radio-group label="Select an option" value="1">
+  <sl-radio-button name="option" value="1">Option 1</sl-radio-button>
   <sl-radio-button name="option" value="2">Option 2</sl-radio-button>
   <sl-radio-button name="option" value="3">Option 3</sl-radio-button>
 </sl-radio-group>
@@ -78,8 +72,8 @@ const App = () => (
 import { SlRadioButton, SlRadioGroup } from '@shoelace-style/shoelace/dist/react';
 
 const App = () => (
-  <SlRadioGroup label="Select an option">
-    <SlRadioButton name="option" value="1" checked>
+  <SlRadioGroup label="Select an option" value="1">
+    <SlRadioButton name="option" value="1">
       Option 1
     </SlRadioButton>
     <SlRadioButton name="option" value="2">
@@ -92,4 +86,141 @@ const App = () => (
 );
 ```
 
+### Validation
+
+Setting the `required` attribute to make selecting an option mandatory. If a value has not been selected, it will prevent the form from submitting and display an error message.
+
+```html preview
+<form class="validation">
+  <sl-radio-group label="Select an option" required>
+    <sl-radio name="a" value="1">Not me</sl-radio>
+    <sl-radio name="a" value="2">Me neither</sl-radio>
+    <sl-radio name="a" value="3">Choose me</sl-radio>
+  </sl-radio-group>
+  <br />
+  <sl-button type="submit" variant="primary">Submit</sl-button>
+</form>
+
+<script>
+  const form = document.querySelector('.validation');
+
+  // Handle form submit
+  form.addEventListener('submit', event => {
+    event.preventDefault();
+    alert('All fields are valid!');
+  });
+</script>
+```
+
+```jsx react
+import { SlButton, SlIcon, SlRadio, SlRadioGroup } from '@shoelace-style/shoelace/dist/react';
+const App = () => {
+  function handleSubmit(event) {
+    event.preventDefault();
+    alert('All fields are valid!');
+  }
+
+  return (
+    <form class="custom-validity" onSubmit={handleSubmit} required>
+      <SlRadioGroup label="Select an option" onSlChange={handleChange}>
+        <SlRadio name="a" value="1">
+          Not me
+        </SlRadio>
+        <SlRadio name="a" value="2">
+          Me neither
+        </SlRadio>
+        <SlRadio name="a" value="3">
+          Choose me
+        </SlRadio>
+      </SlRadioGroup>
+      <br />
+      <SlButton type="submit" variant="primary">
+        Submit
+      </SlButton>
+    </form>
+  );
+};
+```
+
+#### Custom Validity
+
+Use the `setCustomValidity()` method to set a custom validation message. This will prevent the form from submitting and make the browser display the error message you provide. To clear the error, call this function with an empty string.
+
+```html preview
+<form class="custom-validity">
+  <sl-radio-group label="Select an option" value="1">
+    <sl-radio name="a" value="1">Not me</sl-radio>
+    <sl-radio name="a" value="2">Me neither</sl-radio>
+    <sl-radio name="a" value="3">Choose me</sl-radio>
+  </sl-radio-group>
+  <br />
+  <sl-button type="submit" variant="primary">Submit</sl-button>
+</form>
+
+<script>
+  const form = document.querySelector('.custom-validity');
+  const radioGroup = form.querySelector('sl-radio-group');
+  const errorMessage = 'You must choose the last option';
+
+  // Set initial validity as soon as the element is defined
+  customElements.whenDefined('sl-radio-group').then(() => {
+    radioGroup.setCustomValidity(errorMessage);
+  });
+
+  // Update validity when a selection is made
+  form.addEventListener('sl-change', () => {
+    const isValid = radioGroup.value === '3';
+    radioGroup.setCustomValidity(isValid ? '' : errorMessage);
+  });
+
+  // Handle form submit
+  form.addEventListener('submit', event => {
+    event.preventDefault();
+    alert('All fields are valid!');
+  });
+</script>
+```
+
+```jsx react
+import { useEffect, useRef } from 'react';
+import { SlButton, SlIcon, SlRadio, SlRadioGroup } from '@shoelace-style/shoelace/dist/react';
+const App = () => {
+  const radioGroup = useRef(null);
+  const errorMessage = 'You must choose this option';
+
+  function handleChange() {
+    radioGroup.current.setCustomValidity(radioGroup.current.value === '3' ? '' : errorMessage);
+  }
+
+  function handleSubmit(event) {
+    event.preventDefault();
+    alert('All fields are valid!');
+  }
+
+  useEffect(() => {
+    radio.current.setCustomValidity(errorMessage);
+  }, []);
+
+  return (
+    <form class="custom-validity" onSubmit={handleSubmit}>
+      <SlRadioGroup ref={radioGroup} label="Select an option" value="1" onSlChange={handleChange}>
+        <SlRadio name="a" value="1">
+          Not me
+        </SlRadio>
+        <SlRadio name="a" value="2">
+          Me neither
+        </SlRadio>
+        <SlRadio name="a" value="3">
+          Choose me
+        </SlRadio>
+      </SlRadioGroup>
+      <br />
+      <SlButton type="submit" variant="primary">
+        Submit
+      </SlButton>
+    </form>
+  );
+};
+```
+
 [component-metadata:sl-radio-group]