diff --git a/.changeset/server-island-slot-scripts.md b/.changeset/server-island-slot-scripts.md
new file mode 100644
index 000000000000..3066706588e2
--- /dev/null
+++ b/.changeset/server-island-slot-scripts.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes a case where `<script>` tags from components passed as slots to server islands were not included in the response
diff --git a/packages/astro/src/runtime/server/render/server-islands.ts b/packages/astro/src/runtime/server/render/server-islands.ts
index c4de293837ad..9ec3424eac8c 100644
--- a/packages/astro/src/runtime/server/render/server-islands.ts
+++ b/packages/astro/src/runtime/server/render/server-islands.ts
@@ -5,7 +5,7 @@ import { renderChild } from './any.js';
 import { createThinHead, type ThinHead } from './astro/head-and-content.js';
 import type { RenderDestination } from './common.js';
 import { createRenderInstruction } from './instruction.js';
-import { type ComponentSlots, renderSlotToString } from './slot.js';
+import { type ComponentSlots, type SlotString, renderSlotToString } from './slot.js';
 
 const internalProps = new Set([
 	'server:component-path',
@@ -158,7 +158,20 @@ export class ServerIslandComponent {
 		for (const name in this.slots) {
 			if (name !== 'fallback') {
 				const content = await renderSlotToString(this.result, this.slots[name]);
-				renderedSlots[name] = content.toString();
+				let slotHtml = content.toString();
+				// Append script instructions so that components passed as slots
+				// to server:defer components retain their scripts in the island response.
+				// renderSlotToString returns a SlotString (typed as string) that carries
+				// render instructions stripped from the HTML content.
+				const slotContent = content as unknown as SlotString;
+				if (Array.isArray(slotContent.instructions)) {
+					for (const instruction of slotContent.instructions) {
+						if (instruction.type === 'script') {
+							slotHtml += instruction.content;
+						}
+					}
+				}
+				renderedSlots[name] = slotHtml;
 			}
 		}
 
diff --git a/packages/astro/test/fixtures/server-islands/ssr/src/components/ScriptedCounter.astro b/packages/astro/test/fixtures/server-islands/ssr/src/components/ScriptedCounter.astro
new file mode 100644
index 000000000000..35bb766b5d43
--- /dev/null
+++ b/packages/astro/test/fixtures/server-islands/ssr/src/components/ScriptedCounter.astro
@@ -0,0 +1,17 @@
+---
+---
+<div class="counter">
+  <span data-count>0</span>
+  <button data-increment>Increment</button>
+</div>
+
+<script>
+  document.querySelectorAll("[data-increment]").forEach((btn) => {
+    btn.addEventListener("click", () => {
+      const countEl = btn.previousElementSibling;
+      if (countEl) {
+        countEl.textContent = String(Number(countEl.textContent) + 1);
+      }
+    });
+  });
+</script>
diff --git a/packages/astro/test/fixtures/server-islands/ssr/src/components/Wrapper.astro b/packages/astro/test/fixtures/server-islands/ssr/src/components/Wrapper.astro
new file mode 100644
index 000000000000..f4c3cfc62527
--- /dev/null
+++ b/packages/astro/test/fixtures/server-islands/ssr/src/components/Wrapper.astro
@@ -0,0 +1,5 @@
+---
+---
+<div id="wrapper">
+  <slot name="content" />
+</div>
diff --git a/packages/astro/test/fixtures/server-islands/ssr/src/pages/slot-with-script.astro b/packages/astro/test/fixtures/server-islands/ssr/src/pages/slot-with-script.astro
new file mode 100644
index 000000000000..2db634722b90
--- /dev/null
+++ b/packages/astro/test/fixtures/server-islands/ssr/src/pages/slot-with-script.astro
@@ -0,0 +1,15 @@
+---
+import Wrapper from '../components/Wrapper.astro';
+import ScriptedCounter from '../components/ScriptedCounter.astro';
+---
+<html>
+<head>
+  <title>Slot with script</title>
+</head>
+<body>
+  <Wrapper server:defer>
+    <ScriptedCounter slot="content" />
+    <div slot="fallback">Loading...</div>
+  </Wrapper>
+</body>
+</html>
diff --git a/packages/astro/test/server-islands.test.js b/packages/astro/test/server-islands.test.js
index 330441add0c1..dfcaf8931e53 100644
--- a/packages/astro/test/server-islands.test.js
+++ b/packages/astro/test/server-islands.test.js
@@ -245,6 +245,20 @@ describe('Server islands', () => {
 				assert.equal(fetchMatch.length, 2, 'should include props in the query string');
 				assert.equal(fetchMatch[1], '', 'should not include encrypted empty props');
 			});
+
+			it('includes script from slotted component in island response', async () => {
+				const res = await fixture.fetch('/slot-with-script');
+				assert.equal(res.status, 200);
+				const html = await res.text();
+				// Extract the island fetch URL from the page
+				const urlMatch = html.match(/fetch\('(\/_server-islands\/Wrapper\?[^']+)'/);
+				assert.ok(urlMatch, 'should have a server island fetch URL');
+				const islandRes = await fixture.fetch(urlMatch[1]);
+				assert.equal(islandRes.status, 200);
+				const islandHtml = await islandRes.text();
+				assert.ok(islandHtml.includes('<script'), 'island response should include the script tag from the slotted component');
+				assert.ok(islandHtml.includes('data-increment'), 'island response should include the slotted component HTML');
+			});
 		});
 
 		describe('prod', () => {
