diff --git a/asv_bench/benchmarks/index_object.py b/asv_bench/benchmarks/index_object.py
index 11ff5444223d0..908eaa3a9d214 100644
--- a/asv_bench/benchmarks/index_object.py
+++ b/asv_bench/benchmarks/index_object.py
@@ -181,7 +181,7 @@ def time_get_loc(self):
         self.ind.get_loc(0)
 
 
-class IntervalIndexMethod(object):
+class IntervalIndexMethod:
     # GH 24813
     params = [10**3, 10**5]
 
diff --git a/ci/code_checks.sh b/ci/code_checks.sh
index 9a95b7887cfab..e7444fe56ab4d 100755
--- a/ci/code_checks.sh
+++ b/ci/code_checks.sh
@@ -141,7 +141,7 @@ if [[ -z "$CHECK" || "$CHECK" == "patterns" ]]; then
     RET=$(($RET + $?)) ; echo $MSG "DONE"
 
     MSG='Check for python2 new-style classes' ; echo $MSG
-    invgrep -R --include="*.py" -E "class\s\S*\(object\):" pandas scripts
+    invgrep -R --include="*.py" --include="*.pyx" -E "class\s\S*\(object\):" pandas scripts
     RET=$(($RET + $?)) ; echo $MSG "DONE"
 
     MSG='Check for backticks incorrectly rendering because of missing spaces' ; echo $MSG
diff --git a/pandas/_libs/algos.pyx b/pandas/_libs/algos.pyx
index 663411ad984c2..b0533383ac3b1 100644
--- a/pandas/_libs/algos.pyx
+++ b/pandas/_libs/algos.pyx
@@ -50,7 +50,7 @@ cdef inline bint are_diff(object left, object right):
         return left != right
 
 
-class Infinity(object):
+class Infinity:
     """ provide a positive Infinity comparison method for ranking """
 
     __lt__ = lambda self, other: False
@@ -62,7 +62,7 @@ class Infinity(object):
     __ge__ = lambda self, other: not missing.checknull(other)
 
 
-class NegInfinity(object):
+class NegInfinity:
     """ provide a negative Infinity comparison method for ranking """
 
     __lt__ = lambda self, other: (not isinstance(other, NegInfinity) and
diff --git a/pandas/_libs/interval.pyx b/pandas/_libs/interval.pyx
index 173be9398b634..da1bbb8dc130f 100644
--- a/pandas/_libs/interval.pyx
+++ b/pandas/_libs/interval.pyx
@@ -30,7 +30,7 @@ from pandas._libs.tslibs.timezones cimport tz_compare
 _VALID_CLOSED = frozenset(['left', 'right', 'both', 'neither'])
 
 
-cdef class IntervalMixin(object):
+cdef class IntervalMixin:
 
     @property
     def closed_left(self):
diff --git a/pandas/_libs/lib.pyx b/pandas/_libs/lib.pyx
index d80cc482be5b3..0ffbfa0b1f462 100644
--- a/pandas/_libs/lib.pyx
+++ b/pandas/_libs/lib.pyx
@@ -935,7 +935,7 @@ except AttributeError:
     pass
 
 
-cdef class Seen(object):
+cdef class Seen:
     """
     Class for keeping track of the types of elements
     encountered when trying to perform type conversions.
diff --git a/pandas/_libs/properties.pyx b/pandas/_libs/properties.pyx
index d2fbf5aa66fbf..98b2e2888fb21 100644
--- a/pandas/_libs/properties.pyx
+++ b/pandas/_libs/properties.pyx
@@ -6,7 +6,7 @@ from cpython cimport (
     PyDict_Contains, PyDict_GetItem, PyDict_SetItem)
 
 
-cdef class CachedProperty(object):
+cdef class CachedProperty:
 
     cdef readonly:
         object func, name, __doc__
@@ -44,7 +44,7 @@ cdef class CachedProperty(object):
 cache_readonly = CachedProperty
 
 
-cdef class AxisProperty(object):
+cdef class AxisProperty:
 
     cdef readonly:
         Py_ssize_t axis
diff --git a/pandas/_libs/sparse.pyx b/pandas/_libs/sparse.pyx
index 5471c8184e458..fb8e0026556ee 100644
--- a/pandas/_libs/sparse.pyx
+++ b/pandas/_libs/sparse.pyx
@@ -614,7 +614,7 @@ cdef class BlockIndex(SparseIndex):
         pass
 
 
-cdef class BlockMerge(object):
+cdef class BlockMerge:
     """
     Object-oriented approach makes sharing state between recursive functions a
     lot easier and reduces code duplication
diff --git a/pandas/_libs/tslibs/frequencies.pyx b/pandas/_libs/tslibs/frequencies.pyx
index fb74fb08286a3..eac1d31261602 100644
--- a/pandas/_libs/tslibs/frequencies.pyx
+++ b/pandas/_libs/tslibs/frequencies.pyx
@@ -22,7 +22,7 @@ INVALID_FREQ_ERR_MSG = "Invalid frequency: {0}"
 # Period codes
 
 
-class FreqGroup(object):
+class FreqGroup:
     FR_ANN = 1000
     FR_QTR = 2000
     FR_MTH = 3000
diff --git a/pandas/_libs/tslibs/offsets.pyx b/pandas/_libs/tslibs/offsets.pyx
index 9d5151f05b45b..ed1d7cd4c76e7 100644
--- a/pandas/_libs/tslibs/offsets.pyx
+++ b/pandas/_libs/tslibs/offsets.pyx
@@ -312,7 +312,7 @@ class ApplyTypeError(TypeError):
 # ---------------------------------------------------------------------
 # Base Classes
 
-class _BaseOffset(object):
+class _BaseOffset:
     """
     Base class for DateOffset methods that are not overridden by subclasses
     and will (after pickle errors are resolved) go into a cdef class.
@@ -533,7 +533,7 @@ class BaseOffset(_BaseOffset):
         return -self + other
 
 
-class _Tick(object):
+class _Tick:
     """
     dummy class to mix into tseries.offsets.Tick so that in tslibs.period we
     can do isinstance checks on _Tick and avoid importing tseries.offsets
diff --git a/pandas/_libs/tslibs/parsing.pyx b/pandas/_libs/tslibs/parsing.pyx
index f6f52efa951fe..7cf079af2ac29 100644
--- a/pandas/_libs/tslibs/parsing.pyx
+++ b/pandas/_libs/tslibs/parsing.pyx
@@ -660,7 +660,7 @@ def try_parse_datetime_components(object[:] years,
 # Thus, we port the class over so that both issues are resolved.
 #
 # Copyright (c) 2017 - dateutil contributors
-class _timelex(object):
+class _timelex:
     def __init__(self, instream):
         if getattr(instream, 'decode', None) is not None:
             instream = instream.decode()
diff --git a/pandas/_libs/tslibs/period.pyx b/pandas/_libs/tslibs/period.pyx
index 624cad2bfa95a..8f190751951f1 100644
--- a/pandas/_libs/tslibs/period.pyx
+++ b/pandas/_libs/tslibs/period.pyx
@@ -1557,7 +1557,7 @@ class IncompatibleFrequency(ValueError):
     pass
 
 
-cdef class _Period(object):
+cdef class _Period:
 
     cdef readonly:
         int64_t ordinal
diff --git a/pandas/_libs/tslibs/resolution.pyx b/pandas/_libs/tslibs/resolution.pyx
index e02e2b3fe8f3d..a9a63f8120851 100644
--- a/pandas/_libs/tslibs/resolution.pyx
+++ b/pandas/_libs/tslibs/resolution.pyx
@@ -133,7 +133,7 @@ def get_freq_group(freq):
     return (freq // 1000) * 1000
 
 
-class Resolution(object):
+class Resolution:
 
     # Note: cython won't allow us to reference the cdef versions at the
     # module level
diff --git a/pandas/_libs/tslibs/strptime.pyx b/pandas/_libs/tslibs/strptime.pyx
index 527d2da8e3182..642f306f80bda 100644
--- a/pandas/_libs/tslibs/strptime.pyx
+++ b/pandas/_libs/tslibs/strptime.pyx
@@ -363,7 +363,7 @@ def _getlang():
     return locale.getlocale(locale.LC_TIME)
 
 
-class LocaleTime(object):
+class LocaleTime:
     """Stores and handles locale-specific information related to time.
 
     ATTRIBUTES:
diff --git a/pandas/_libs/tslibs/timestamps.pyx b/pandas/_libs/tslibs/timestamps.pyx
index 7340e716ec651..c76346e25cdb9 100644
--- a/pandas/_libs/tslibs/timestamps.pyx
+++ b/pandas/_libs/tslibs/timestamps.pyx
@@ -57,7 +57,7 @@ cdef inline object create_timestamp_from_ts(int64_t value,
     return ts_base
 
 
-class RoundTo(object):
+class RoundTo:
     """
     enumeration defining the available rounding modes
 
diff --git a/pandas/io/msgpack/_packer.pyx b/pandas/io/msgpack/_packer.pyx
index 8e2d943d8ddb1..a0d2b013c8e9d 100644
--- a/pandas/io/msgpack/_packer.pyx
+++ b/pandas/io/msgpack/_packer.pyx
@@ -44,7 +44,7 @@ cdef extern from "../../src/msgpack/pack.h":
 cdef int DEFAULT_RECURSE_LIMIT=511
 
 
-cdef class Packer(object):
+cdef class Packer:
     """
     MessagePack Packer
 
diff --git a/pandas/io/msgpack/_unpacker.pyx b/pandas/io/msgpack/_unpacker.pyx
index 9bbfe749ef9ba..8734990c44da0 100644
--- a/pandas/io/msgpack/_unpacker.pyx
+++ b/pandas/io/msgpack/_unpacker.pyx
@@ -173,7 +173,7 @@ def unpack(object stream, object object_hook=None, object list_hook=None,
                    encoding=encoding, unicode_errors=unicode_errors)
 
 
-cdef class Unpacker(object):
+cdef class Unpacker:
     """Streaming unpacker.
 
     arguments:
diff --git a/pandas/io/sas/sas.pyx b/pandas/io/sas/sas.pyx
index ed6a3efae137c..0aec958d1f9bd 100644
--- a/pandas/io/sas/sas.pyx
+++ b/pandas/io/sas/sas.pyx
@@ -211,7 +211,7 @@ cdef:
     int subheader_pointers_offset = const.subheader_pointers_offset
 
 
-cdef class Parser(object):
+cdef class Parser:
 
     cdef:
         int column_count