diff --git a/Tests/test_image.py b/Tests/test_image.py
index 487035a3ef9..b9c57770c70 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -909,27 +909,27 @@ def test_zero_tobytes(self, size):
     def test_has_transparency_data(self):
         for mode in ("1", "L", "P", "RGB"):
             im = Image.new(mode, (1, 1))
-            assert not im.has_transparency_data()
+            assert not im.has_transparency_data
 
         for mode in ("LA", "La", "PA", "RGBA", "RGBa"):
             im = Image.new(mode, (1, 1))
-            assert im.has_transparency_data()
+            assert im.has_transparency_data
 
         # P mode with "transparency" info
         with Image.open("Tests/images/first_frame_transparency.gif") as im:
             assert "transparency" in im.info
-            assert im.has_transparency_data()
+            assert im.has_transparency_data
 
         # RGB mode with "transparency" info
         with Image.open("Tests/images/rgb_trns.png") as im:
             assert "transparency" in im.info
-            assert im.has_transparency_data()
+            assert im.has_transparency_data
 
         # P mode with RGBA palette
         im = Image.new("RGBA", (1, 1)).convert("P")
         assert im.mode == "P"
         assert im.palette.mode == "RGBA"
-        assert im.has_transparency_data()
+        assert im.has_transparency_data
 
     def test_apply_transparency(self):
         im = Image.new("P", (1, 1))
diff --git a/docs/reference/Image.rst b/docs/reference/Image.rst
index ae8f923cb7a..e356469b673 100644
--- a/docs/reference/Image.rst
+++ b/docs/reference/Image.rst
@@ -195,7 +195,7 @@ This helps to get the bounding box coordinates of the input image::
 .. automethod:: PIL.Image.Image.getpalette
 .. automethod:: PIL.Image.Image.getpixel
 .. automethod:: PIL.Image.Image.getprojection
-.. automethod:: PIL.Image.Image.has_transparency_data
+.. autoproperty:: PIL.Image.Image.has_transparency_data
 .. automethod:: PIL.Image.Image.histogram
 .. automethod:: PIL.Image.Image.paste
 .. automethod:: PIL.Image.Image.point
diff --git a/src/PIL/Image.py b/src/PIL/Image.py
index 842e5db56ea..244d2e43520 100644
--- a/src/PIL/Image.py
+++ b/src/PIL/Image.py
@@ -1531,6 +1531,7 @@ def getpalette(self, rawmode="RGB"):
             rawmode = mode
         return list(self.im.getpalette(mode, rawmode))
 
+    @property
     def has_transparency_data(self) -> bool:
         """
         Determine if an image has transparency data, whether in the form of an
diff --git a/src/PIL/WebPImagePlugin.py b/src/PIL/WebPImagePlugin.py
index 86169b78085..fa34769e77f 100644
--- a/src/PIL/WebPImagePlugin.py
+++ b/src/PIL/WebPImagePlugin.py
@@ -332,7 +332,7 @@ def _save(im, fp, filename):
     exact = 1 if im.encoderinfo.get("exact") else 0
 
     if im.mode not in _VALID_WEBP_LEGACY_MODES:
-        im = im.convert("RGBA" if im.has_transparency_data() else "RGB")
+        im = im.convert("RGBA" if im.has_transparency_data else "RGB")
 
     data = _webp.WebPEncode(
         im.tobytes(),