diff --git a/psutil/_psbsd.py b/psutil/_psbsd.py
index 76d6d588c..990ecd51b 100644
--- a/psutil/_psbsd.py
+++ b/psutil/_psbsd.py
@@ -463,7 +463,8 @@ def terminal(self):
 
     @wrap_exceptions
     def ppid(self):
-        return cext.proc_ppid(self.pid)
+        self._ppid = cext.proc_ppid(self.pid)
+        return self._ppid
 
     @wrap_exceptions
     def uids(self):
diff --git a/psutil/_psosx.py b/psutil/_psosx.py
index 77e5ed58e..c5021ce14 100644
--- a/psutil/_psosx.py
+++ b/psutil/_psosx.py
@@ -250,7 +250,8 @@ def environ(self):
 
     @wrap_exceptions
     def ppid(self):
-        return cext.proc_ppid(self.pid)
+        self._ppid = cext.proc_ppid(self.pid)
+        return self._ppid
 
     @wrap_exceptions
     def cwd(self):
diff --git a/psutil/_pssunos.py b/psutil/_pssunos.py
index bca545272..82fa38f7a 100644
--- a/psutil/_pssunos.py
+++ b/psutil/_pssunos.py
@@ -359,7 +359,8 @@ def nice_set(self, value):
 
     @wrap_exceptions
     def ppid(self):
-        return cext.proc_basic_info(self.pid, self._procfs_path)[0]
+        self._ppid = cext.proc_basic_info(self.pid, self._procfs_path)[0]
+        return self._ppid
 
     @wrap_exceptions
     def uids(self):