diff --git a/.changeset/six-lobsters-jog.md b/.changeset/six-lobsters-jog.md
new file mode 100644
index 0000000..88e52db
--- /dev/null
+++ b/.changeset/six-lobsters-jog.md
@@ -0,0 +1,5 @@
+---
+"prettier-plugin-astro": minor
+---
+
+Do not delete line breaks and indentation of lines in class attribute
diff --git a/src/printer/utils.ts b/src/printer/utils.ts
index 2881148..2e42f85 100644
--- a/src/printer/utils.ts
+++ b/src/printer/utils.ts
@@ -198,7 +198,12 @@ export function trimTextNodeRight(node: TextNode): void {
 }
 
 export function printClassNames(value: string) {
-	return value.trim().split(/\s+/).join(' ');
+	const lines = value.trim().split(/[\r\n]+/);
+	const formattedLines = lines.map((line) => {
+		const spaces = line.match(/^\s+/);
+		return (spaces ? spaces[0] : '') + line.trim().split(/\s+/).join(' ');
+	});
+	return formattedLines.join('\n');
 }
 
 /** dedent string & return tabSize (the last part is what we need) */
diff --git a/test/fixtures/basic/html-class-attribute-with-line-breaks/input.astro b/test/fixtures/basic/html-class-attribute-with-line-breaks/input.astro
new file mode 100644
index 0000000..803d363
--- /dev/null
+++ b/test/fixtures/basic/html-class-attribute-with-line-breaks/input.astro
@@ -0,0 +1,3 @@
+<div class="  sm:p-0   p-0 
+		m-2  sm:m-1  
+		border "></div>
diff --git a/test/fixtures/basic/html-class-attribute-with-line-breaks/output.astro b/test/fixtures/basic/html-class-attribute-with-line-breaks/output.astro
new file mode 100644
index 0000000..20daa1d
--- /dev/null
+++ b/test/fixtures/basic/html-class-attribute-with-line-breaks/output.astro
@@ -0,0 +1,3 @@
+<div class="sm:p-0 p-0
+		m-2 sm:m-1
+		border"></div>
diff --git a/test/tests/basic.test.ts b/test/tests/basic.test.ts
index 5bc5c30..6661adc 100644
--- a/test/tests/basic.test.ts
+++ b/test/tests/basic.test.ts
@@ -17,6 +17,12 @@ test('Can format HTML custom elements', files, 'basic/html-custom-elements');
 
 test('Can properly format the class attribute', files, 'basic/html-class-attribute');
 
+test(
+	'Can properly format the class attribute with line breaks',
+	files,
+	'basic/html-class-attribute-with-line-breaks'
+);
+
 test('Can format long self-closing tags with multiple attributes', files, 'basic/self-closing');
 
 test('Can properly format inline tags and respect whitespace', files, 'basic/inline-whitespace');