diff --git a/sphinx/util/_pathlib.py b/sphinx/util/_pathlib.py
index db22c927a1c..59980e96114 100644
--- a/sphinx/util/_pathlib.py
+++ b/sphinx/util/_pathlib.py
@@ -38,6 +38,12 @@ def __add__(self, other):
             warnings.warn(_MSG, RemovedInSphinx80Warning, stacklevel=2)
             return self.__str__() + other
 
+        def __bool__(self):
+            if not self.__str__():
+                warnings.warn(_MSG, RemovedInSphinx80Warning, stacklevel=2)
+                return False
+            return True
+
         def __contains__(self, item):
             warnings.warn(_MSG, RemovedInSphinx80Warning, stacklevel=2)
             return item in self.__str__()
@@ -79,6 +85,12 @@ def __add__(self, other):
             warnings.warn(_MSG, RemovedInSphinx80Warning, stacklevel=2)
             return self.__str__() + other
 
+        def __bool__(self):
+            if not self.__str__():
+                warnings.warn(_MSG, RemovedInSphinx80Warning, stacklevel=2)
+                return False
+            return True
+
         def __contains__(self, item):
             warnings.warn(_MSG, RemovedInSphinx80Warning, stacklevel=2)
             return item in self.__str__()