diff --git a/docs/reference-guides/core-blocks.md b/docs/reference-guides/core-blocks.md
index b8beeef967900..4972e19886137 100644
--- a/docs/reference-guides/core-blocks.md
+++ b/docs/reference-guides/core-blocks.md
@@ -581,7 +581,7 @@ Displays the title of a post, page, or any other content-type. ([Source](https:/
 
 -	**Name:** core/post-title
 -	**Category:** theme
--	**Supports:** align (full, wide), color (background, gradients, link, text), spacing (margin), typography (fontSize, lineHeight), ~~html~~
+-	**Supports:** align (full, wide), color (background, gradients, link, text), spacing (margin, padding), typography (fontSize, lineHeight), ~~html~~
 -	**Attributes:** isLink, level, linkTarget, rel, textAlign
 
 ## Preformatted
diff --git a/packages/block-library/src/post-title/block.json b/packages/block-library/src/post-title/block.json
index 4db50e33b1d51..015896ff1bad0 100644
--- a/packages/block-library/src/post-title/block.json
+++ b/packages/block-library/src/post-title/block.json
@@ -42,7 +42,8 @@
 			}
 		},
 		"spacing": {
-			"margin": true
+			"margin": true,
+			"padding": true
 		},
 		"typography": {
 			"fontSize": true,
diff --git a/packages/block-library/src/post-title/style.scss b/packages/block-library/src/post-title/style.scss
index 415d04d3fc57b..abeb4454bcb2c 100644
--- a/packages/block-library/src/post-title/style.scss
+++ b/packages/block-library/src/post-title/style.scss
@@ -1,5 +1,7 @@
 .wp-block-post-title {
 	word-break: break-word;
+	// This block has customizable padding, border-box makes that more predictable.
+	box-sizing: border-box;
 
 	a {
 		display: inline-block;