diff --git a/news/changelog-1.11.md b/news/changelog-1.11.md
index 754f3da5a13..d87c3aa27de 100644
--- a/news/changelog-1.11.md
+++ b/news/changelog-1.11.md
@@ -51,6 +51,7 @@ All changes included in 1.11:
 
 - ([#14996](https://github.com/quarto-dev/quarto-cli/pull/14996)): Fix `controls: auto` and `previewLinks: auto` set at the top level of a revealjs document's front matter producing a presentation that fails to load, because `auto` was written unquoted into the generated JavaScript.
 - ([#15007](https://github.com/quarto-dev/quarto-cli/pull/15007)): Fix Home/End on a focused tabset tab also jumping to the first or last slide in addition to switching tabs.
+- ([#15014](https://github.com/quarto-dev/quarto-cli/issues/15014)): Fix code blocks at the end of a callout losing their bottom spacing, which made the code block border touch the callout border in untitled `appearance="simple"` callouts (regression introduced in v1.8.15).
 
 ### `typst`
 
diff --git a/src/resources/formats/revealjs/quarto.scss b/src/resources/formats/revealjs/quarto.scss
index a09f78152a5..2fbda00a504 100644
--- a/src/resources/formats/revealjs/quarto.scss
+++ b/src/resources/formats/revealjs/quarto.scss
@@ -920,7 +920,7 @@ kbd {
           > :last-child {
             margin-bottom: var(--r-block-margin);
           }
-          > :last-child:not(div.sourceCode) {
+          > :last-child:not(div.sourceCode, div.code-copy-outer-scaffold) {
             padding-bottom: 0.5rem;
             margin-bottom: 0;
           }
@@ -970,9 +970,11 @@ kbd {
       }
       .callout-body {
         > .callout-content {
-          // Margin needs to be added when last child is div.sourceCode
-          // Other code cell border is mixed with callout border
-          > div.sourceCode:last-child {
+          // Margin needs to be added when the last child is a code block
+          // (div.sourceCode, or the code-copy scaffold wrapping it).
+          // Otherwise the code block border merges with the callout border.
+          > div.sourceCode:last-child,
+          > div.code-copy-outer-scaffold:last-child {
             margin-bottom: 1rem;
           }
           > :first-child {
diff --git a/tests/docs/playwright/revealjs/callouts/callout-code-last.qmd b/tests/docs/playwright/revealjs/callouts/callout-code-last.qmd
new file mode 100644
index 00000000000..347d82a7887
--- /dev/null
+++ b/tests/docs/playwright/revealjs/callouts/callout-code-last.qmd
@@ -0,0 +1,54 @@
+---
+title: callout ending with a code block
+format: revealjs
+---
+
+## Default titled, ends with code
+
+::: {#default-titled-code .callout-note title="Titled"}
+Some text before the code.
+
+```python
+1 + 1
+```
+:::
+
+## Simple untitled, ends with code
+
+::: {#simple-untitled-code .callout-note appearance="simple"}
+Some text before the code.
+
+```python
+1 + 1
+```
+:::
+
+## Simple titled, ends with code
+
+::: {#simple-titled-code .callout-note appearance="simple" title="Titled"}
+Some text before the code.
+
+```python
+1 + 1
+```
+:::
+
+## Default titled, ends with paragraph
+
+::: {#default-titled-paragraph .callout-note title="Titled"}
+```python
+1 + 1
+```
+
+Some text after the code.
+:::
+
+## Simple untitled, ends with paragraph
+
+::: {#simple-untitled-paragraph .callout-note appearance="simple"}
+```python
+1 + 1
+```
+
+Some text after the code.
+:::
diff --git a/tests/integration/playwright/tests/revealjs-callouts.spec.ts b/tests/integration/playwright/tests/revealjs-callouts.spec.ts
new file mode 100644
index 00000000000..29b21044e95
--- /dev/null
+++ b/tests/integration/playwright/tests/revealjs-callouts.spec.ts
@@ -0,0 +1,90 @@
+import { test, expect } from '@playwright/test';
+import { expectCloseTo } from '../src/utils';
+
+// Space below the last block of a callout, in CSS px, for callouts whose last
+// block is a code block (wrapped in the code-copy scaffold) or a paragraph.
+// Reveal scales the slide, so the measured gap is divided by Reveal.getScale()
+// and the callout's own bottom border is subtracted.
+// https://github.com/quarto-dev/quarto-cli/issues/15014
+type ExpectedGap = '--r-block-margin' | '1rem' | 0;
+
+interface CalloutCase {
+  name: string;
+  slide: string;
+  callout: string;
+  lastBlock: string;
+  expectedGap: ExpectedGap;
+}
+
+const testCases: CalloutCase[] = [
+  {
+    name: 'default titled callout ending with code',
+    slide: 'default-titled-ends-with-code',
+    callout: 'default-titled-code',
+    lastBlock: 'div.sourceCode',
+    expectedGap: '--r-block-margin',
+  },
+  {
+    name: 'simple untitled callout ending with code',
+    slide: 'simple-untitled-ends-with-code',
+    callout: 'simple-untitled-code',
+    lastBlock: 'div.sourceCode',
+    expectedGap: '1rem',
+  },
+  {
+    name: 'simple titled callout ending with code',
+    slide: 'simple-titled-ends-with-code',
+    callout: 'simple-titled-code',
+    lastBlock: 'div.sourceCode',
+    expectedGap: '--r-block-margin',
+  },
+  {
+    name: 'default titled callout ending with paragraph',
+    slide: 'default-titled-ends-with-paragraph',
+    callout: 'default-titled-paragraph',
+    lastBlock: '.callout-content > p:last-child',
+    expectedGap: 0,
+  },
+  {
+    name: 'simple untitled callout ending with paragraph',
+    slide: 'simple-untitled-ends-with-paragraph',
+    callout: 'simple-untitled-paragraph',
+    lastBlock: '.callout-content > p:last-child',
+    expectedGap: '--r-block-margin',
+  },
+];
+
+test.describe('Revealjs callout bottom spacing', () => {
+  for (const { name, slide, callout, lastBlock, expectedGap } of testCases) {
+    test(`${name} has the expected space below the last block`, async ({ page }) => {
+      await page.goto(`./revealjs/callouts/callout-code-last.html#/${slide}`);
+      // Quarto puts the id on a wrapper div and on div.callout; target the one with the border.
+      const calloutBox = page.locator(`div.callout#${callout}`);
+      await expect(calloutBox).toBeVisible();
+      // Reveal adds .ready once layout and scaling are done.
+      await expect(page.locator('.reveal.ready')).toBeAttached();
+
+      const { gap, expected } = await calloutBox.evaluate((el, { lastBlock, expectedGap }) => {
+        // Resolve a CSS length to px in the page.
+        const resolve = (value: string) => {
+          const probe = document.createElement('div');
+          probe.style.cssText = `position:absolute;visibility:hidden;margin-bottom:${value}`;
+          document.body.appendChild(probe);
+          const px = parseFloat(getComputedStyle(probe).marginBottom);
+          probe.remove();
+          return px;
+        };
+        const block = el.querySelector(lastBlock) as HTMLElement;
+        const scale = (window as any).Reveal.getScale();
+        const borderBottom = parseFloat(getComputedStyle(el).borderBottomWidth);
+        const rawGap = el.getBoundingClientRect().bottom - block.getBoundingClientRect().bottom;
+        const expected = expectedGap === 0
+          ? 0
+          : resolve(expectedGap === '1rem' ? '1rem' : `var(${expectedGap})`);
+        return { gap: rawGap / scale - borderBottom, expected };
+      }, { lastBlock, expectedGap });
+
+      expectCloseTo(gap, expected, 1);
+    });
+  }
+});