diff --git a/.gitignore b/.gitignore
index 13a4a63709..a5d0a6318d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ astroid.egg-info/
 .pytest_cache/
 .mypy_cache/
 venv
+doc/_build/
diff --git a/ChangeLog b/ChangeLog
index 75561c9ba6..22e0880722 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,10 @@ What's New in astroid 2.12.0?
 =============================
 Release date: TBA
 
+* Fix signal has no ``connect`` member for PySide2 5.15.2+ and PySide6
+
+  Closes #4040, #5378
+
 * ``astroid`` now requires Python 3.7.2 to run.
 
 * Avoid setting a Call as a base for classes created using ``six.with_metaclass()``.
diff --git a/astroid/brain/brain_qt.py b/astroid/brain/brain_qt.py
index 6b97bf671a..e8bfe88fd1 100644
--- a/astroid/brain/brain_qt.py
+++ b/astroid/brain/brain_qt.py
@@ -10,12 +10,18 @@
 from astroid.manager import AstroidManager
 
 
-def _looks_like_signal(node, signal_name="pyqtSignal"):
-    if "__class__" in node.instance_attrs:
+def _looks_like_signal(
+    node: nodes.FunctionDef, signal_name: str = "pyqtSignal"
+) -> bool:
+    """Detect a Signal node."""
+    klasses = node.instance_attrs.get("__class__", [])
+    # On PySide2 or PySide6 (since  Qt 5.15.2) the Signal class changed locations
+    if node.qname().partition(".")[0] in {"PySide2", "PySide6"}:
+        return any(cls.qname() == "Signal" for cls in klasses)  # pragma: no cover
+    if klasses:
         try:
-            cls = node.instance_attrs["__class__"][0]
-            return cls.name == signal_name
-        except AttributeError:
+            return klasses[0].name == signal_name
+        except AttributeError:  # pragma: no cover
             # return False if the cls does not have a name attribute
             pass
     return False
diff --git a/script/.contributors_aliases.json b/script/.contributors_aliases.json
index 60fabfa86e..2b3c6d877e 100644
--- a/script/.contributors_aliases.json
+++ b/script/.contributors_aliases.json
@@ -169,5 +169,9 @@
   "ville.skytta@iki.fi": {
     "mails": ["ville.skytta@iki.fi", "ville.skytta@upcloud.com"],
     "name": "Ville Skyttä"
+  },
+  "adam.grant.hendry@gmail.com": {
+    "mails": ["adam.grant.hendry@gmail.com"],
+    "name": "Adam Hendry"
   }
 }
diff --git a/tests/unittest_brain_qt.py b/tests/unittest_brain_qt.py
index 93ef4dd110..7e10db70ba 100644
--- a/tests/unittest_brain_qt.py
+++ b/tests/unittest_brain_qt.py
@@ -14,7 +14,7 @@
 HAS_PYQT6 = find_spec("PyQt6")
 
 
-@pytest.mark.skipif(HAS_PYQT6 is None, reason="This test requires the PyQt6 library.")
+@pytest.mark.skipif(HAS_PYQT6 is None, reason="These tests require the PyQt6 library.")
 class TestBrainQt:
     AstroidManager.brain["extension_package_whitelist"] = {"PyQt6"}