diff --git a/CHANGELOG.md b/CHANGELOG.md
index a52f8df41d..564e8a321b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - `Pilot.click`/`Pilot.hover` can't use `Screen` as a selector https://github.com/Textualize/textual/issues/3395
 - App exception when a `Tree` is initialized/mounted with `disabled=True` https://github.com/Textualize/textual/issues/3407
+- Fixed fractional styles to allow integer values https://github.com/Textualize/textual/issues/3414
 
 ### Added
 
diff --git a/src/textual/css/_style_properties.py b/src/textual/css/_style_properties.py
index 658932165e..9667e97c65 100644
--- a/src/textual/css/_style_properties.py
+++ b/src/textual/css/_style_properties.py
@@ -1063,8 +1063,8 @@ def __set__(self, obj: StylesBase, value: float | str | None) -> None:
                 obj.refresh(children=self.children)
             return
 
-        if isinstance(value, float):
-            float_value = value
+        if isinstance(value, (int, float)):
+            float_value = float(value)
         elif isinstance(value, str) and value.endswith("%"):
             float_value = float(Scalar.parse(value).value) / 100
         else:
diff --git a/tests/css/test_styles.py b/tests/css/test_styles.py
index e21572478a..b31ad46548 100644
--- a/tests/css/test_styles.py
+++ b/tests/css/test_styles.py
@@ -148,6 +148,13 @@ def test_opacity_set_invalid_type_error():
         styles.text_opacity = "invalid value"
 
 
+def test_opacity_set_allows_integer_value():
+    """Regression test for https://github.com/Textualize/textual/issues/3414"""
+    styles = RenderStyles(DOMNode(), Styles(), Styles())
+    styles.text_opacity = 0
+    assert styles.text_opacity == 0.0
+
+
 @pytest.mark.parametrize(
     "size_dimension_input,size_dimension_expected_output",
     [