diff --git a/weasyprint/css/validation.py b/weasyprint/css/validation.py
index 7d9f9dd49..0c5fcf60e 100644
--- a/weasyprint/css/validation.py
+++ b/weasyprint/css/validation.py
@@ -882,9 +882,12 @@ def line_height(token):
     """``line-height`` property validation."""
     if get_keyword(token) == 'normal':
         return 'normal'
-    if (token.type in ('NUMBER', 'INTEGER', 'DIMENSION', 'PERCENTAGE') and
-            token.value >= 0):
+    if token.type in ('NUMBER', 'INTEGER', 'PERCENTAGE') and token.value >= 0:
         return Dimension(token.value, token.unit)
+    elif token.type == 'DIMENSION' and token.value >= 0:
+        length = get_length(token)
+        if length:
+            return length
 
 
 @validator()
diff --git a/weasyprint/tests/test_css_validation.py b/weasyprint/tests/test_css_validation.py
index b27867b7f..b87629a70 100644
--- a/weasyprint/tests/test_css_validation.py
+++ b/weasyprint/tests/test_css_validation.py
@@ -495,6 +495,23 @@ def test_font():
     assert_invalid('font: 12px "Invalid" family')
 
 
+@assert_no_logs
+def test_line_height():
+    """Test the ``line-height`` property."""
+    assert expand_to_dict('line-height: 1px') == {'line_height': (1, 'px')}
+    assert expand_to_dict('line-height: 1.1%') == {'line_height': (1.1, '%')}
+    assert expand_to_dict('line-height: 1em') == {'line_height': (1, 'em')}
+    assert expand_to_dict('line-height: 1') == {'line_height': (1, None)}
+    assert expand_to_dict('line-height: 1.3') == {'line_height': (1.3, None)}
+    assert expand_to_dict('line-height: -0') == {'line_height': (0, None)}
+    assert expand_to_dict('line-height: 0px') == {'line_height': (0, 'px')}
+    assert_invalid('line-height: 1deg')
+    assert_invalid('line-height: -1px')
+    assert_invalid('line-height: -1')
+    assert_invalid('line-height: -0.5%')
+    assert_invalid('line-height: 1px 1px')
+
+
 @assert_no_logs
 def test_linear_gradient():
     red = (1, 0, 0, 1)