diff --git a/doc/source/api.rst b/doc/source/api.rst
index a365b874f095d..f64f088e3c8f0 100644
--- a/doc/source/api.rst
+++ b/doc/source/api.rst
@@ -188,7 +188,9 @@ Top-level missing data
    :toctree: generated/
 
    isna
+   isnull
    notna
+   notnull
 
 Top-level conversions
 ~~~~~~~~~~~~~~~~~~~~~
diff --git a/pandas/core/categorical.py b/pandas/core/categorical.py
index 3ef720856f90c..1392ad2f011db 100644
--- a/pandas/core/categorical.py
+++ b/pandas/core/categorical.py
@@ -1165,7 +1165,8 @@ def isna(self):
 
         See also
         --------
-        isna : pandas version
+        isna : top-level isna
+        isnull : alias of isna
         Categorical.notna : boolean inverse of Categorical.isna
 
         """
@@ -1183,7 +1184,7 @@ def isna(self):
 
     def notna(self):
         """
-        Reverse of isna
+        Inverse of isna
 
         Both missing values (-1 in .codes) and NA as a category are detected as
         null.
@@ -1194,7 +1195,8 @@ def notna(self):
 
         See also
         --------
-        notna : pandas version
+        notna : top-level notna
+        notnull : alias of notna
         Categorical.isna : boolean inverse of Categorical.notna
 
         """
diff --git a/pandas/core/dtypes/missing.py b/pandas/core/dtypes/missing.py
index 7611c762540fb..101612893cb02 100644
--- a/pandas/core/dtypes/missing.py
+++ b/pandas/core/dtypes/missing.py
@@ -40,6 +40,7 @@ def isna(obj):
     See also
     --------
     pandas.notna: boolean inverse of pandas.isna
+    pandas.isnull: alias of isna
     """
     return _isna(obj)
 
@@ -206,6 +207,7 @@ def notna(obj):
     See also
     --------
     pandas.isna : boolean inverse of pandas.notna
+    pandas.notnull : alias of notna
     """
     res = isna(obj)
     if is_scalar(res):
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 5eb6645ef78fb..6c72fa648559a 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -3205,6 +3205,22 @@ def _maybe_casted_values(index, labels=None):
     # ----------------------------------------------------------------------
     # Reindex-based selection methods
 
+    @Appender(_shared_docs['isna'] % _shared_doc_kwargs)
+    def isna(self):
+        return super(DataFrame, self).isna()
+
+    @Appender(_shared_docs['isna'] % _shared_doc_kwargs)
+    def isnull(self):
+        return super(DataFrame, self).isnull()
+
+    @Appender(_shared_docs['isna'] % _shared_doc_kwargs)
+    def notna(self):
+        return super(DataFrame, self).notna()
+
+    @Appender(_shared_docs['notna'] % _shared_doc_kwargs)
+    def notnull(self):
+        return super(DataFrame, self).notnull()
+
     def dropna(self, axis=0, how='any', thresh=None, subset=None,
                inplace=False):
         """
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index e1a8c54a1d4f5..8842e6f7bde16 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -4456,13 +4456,18 @@ def asof(self, where, subset=None):
 
         See Also
         --------
-        notna : boolean inverse of isna
+        %(klass)s.notna : boolean inverse of isna
+        %(klass)s.isnull : alias of isna
+        isna : top-level isna
         """
 
-    @Appender(_shared_docs['isna'])
+    @Appender(_shared_docs['isna'] % _shared_doc_kwargs)
     def isna(self):
         return isna(self).__finalize__(self)
-    isnull = isna
+
+    @Appender(_shared_docs['isna'] % _shared_doc_kwargs)
+    def isnull(self):
+        return isna(self).__finalize__(self)
 
     _shared_docs['notna'] = """
         Return a boolean same-sized object indicating if the values are
@@ -4470,13 +4475,18 @@ def isna(self):
 
         See Also
         --------
-        isna : boolean inverse of notna
+        %(klass)s.isna : boolean inverse of notna
+        %(klass)s.notnull : alias of notna
+        notna : top-level notna
         """
 
-    @Appender(_shared_docs['notna'])
+    @Appender(_shared_docs['notna'] % _shared_doc_kwargs)
     def notna(self):
         return notna(self).__finalize__(self)
-    notnull = notna
+
+    @Appender(_shared_docs['notna'] % _shared_doc_kwargs)
+    def notnull(self):
+        return notna(self).__finalize__(self)
 
     def _clip_with_scalar(self, lower, upper, inplace=False):
         if ((lower is not None and np.any(isna(lower))) or
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 931e6df78ebee..fd9abcfb726bf 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -1856,14 +1856,15 @@ def isna(self):
 
         See also
         --------
-        pandas.isna : pandas version
+        isnull : alias of isna
+        pandas.isna : top-level isna
         """
         return self._isnan
     isnull = isna
 
     def notna(self):
         """
-        Reverse of isna
+        Inverse of isna
 
         .. versionadded:: 0.20.0
 
@@ -1873,7 +1874,8 @@ def notna(self):
 
         See also
         --------
-        pandas.notna : pandas version
+        notnull : alias of notna
+        pandas.notna : top-level notna
         """
         return ~self.isna()
     notnull = notna
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 3abd8a8e9350e..fb5819b2748a0 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -2784,6 +2784,22 @@ def to_excel(self, excel_writer, sheet_name='Sheet1', na_rep='',
                     merge_cells=merge_cells, encoding=encoding,
                     inf_rep=inf_rep, verbose=verbose)
 
+    @Appender(generic._shared_docs['isna'] % _shared_doc_kwargs)
+    def isna(self):
+        return super(Series, self).isna()
+
+    @Appender(generic._shared_docs['isna'] % _shared_doc_kwargs)
+    def isnull(self):
+        return super(Series, self).isnull()
+
+    @Appender(generic._shared_docs['isna'] % _shared_doc_kwargs)
+    def notna(self):
+        return super(Series, self).notna()
+
+    @Appender(generic._shared_docs['notna'] % _shared_doc_kwargs)
+    def notnull(self):
+        return super(Series, self).notnull()
+
     def dropna(self, axis=0, inplace=False, **kwargs):
         """
         Return Series without null values