diff --git a/contrib/nagios/check_galaxy.py b/contrib/nagios/check_galaxy.py
index 57da403ec0f..d61ff42d84f 100755
--- a/contrib/nagios/check_galaxy.py
+++ b/contrib/nagios/check_galaxy.py
@@ -73,7 +73,7 @@ tc.agent("Mozilla/5.0 (compatible; check_galaxy/0.2)")
 tc.config('use_tidy', 0)
 
 
-class Browser:
+class Browser(object):
     def __init__(self):
         self.server = server
         self.handler = handler
diff --git a/lib/galaxy/authnz/psa_authnz.py b/lib/galaxy/authnz/psa_authnz.py
index 2d3a2a6b552..25be8b29ce3 100644
--- a/lib/galaxy/authnz/psa_authnz.py
+++ b/lib/galaxy/authnz/psa_authnz.py
@@ -230,7 +230,7 @@ class Strategy(BaseStrategy):
         return self.backend.continue_pipeline(*args, **kwargs)
 
 
-class Storage:
+class Storage(object):
     user = UserAuthnzToken
     nonce = PSANonce
     association = PSAAssociation
diff --git a/lib/galaxy/tools/util/maf_utilities.py b/lib/galaxy/tools/util/maf_utilities.py
index b2c25abb38d..3a5aa531bb2 100644
--- a/lib/galaxy/tools/util/maf_utilities.py
+++ b/lib/galaxy/tools/util/maf_utilities.py
@@ -731,7 +731,7 @@ def get_attributes_from_fasta_header(header):
 
 
 def iter_fasta_alignment(filename):
-    class fastaComponent:
+    class fastaComponent(object):
         def __init__(self, species, text=""):
             self.species = species
             self.text = text
diff --git a/lib/galaxy/tools/wrappers.py b/lib/galaxy/tools/wrappers.py
index 44e003585c1..94818e938a5 100644
--- a/lib/galaxy/tools/wrappers.py
+++ b/lib/galaxy/tools/wrappers.py
@@ -120,7 +120,7 @@ class SelectToolParameterWrapper(ToolParameterValueWrapper):
     attributes are accessible.
     """
 
-    class SelectToolParameterFieldWrapper:
+    class SelectToolParameterFieldWrapper(object):
         """
         Provide access to any field by name or index for this particular value.
         Only applicable for dynamic_options selects, which have more than simple 'options' defined (name, value, selected).
@@ -182,7 +182,7 @@ class DatasetFilenameWrapper(ToolParameterValueWrapper):
     attributes are accessible.
     """
 
-    class MetadataWrapper:
+    class MetadataWrapper(object):
         """
         Wraps a Metadata Collection to return MetadataParameters wrapped
         according to the metadata spec. Methods implemented to match behavior
diff --git a/lib/galaxy/util/streamball.py b/lib/galaxy/util/streamball.py
index c25a9d26710..1ad22d630fb 100644
--- a/lib/galaxy/util/streamball.py
+++ b/lib/galaxy/util/streamball.py
@@ -33,7 +33,7 @@ class StreamBall(object):
     def stream(self, environ, start_response):
         response_write = start_response(self.wsgi_status, self.wsgi_headeritems)
 
-        class tarfileobj:
+        class tarfileobj(object):
             def write(self, *args, **kwargs):
                 response_write(*args, **kwargs)
         tf = tarfile.open(mode=self.mode, fileobj=tarfileobj())
diff --git a/scripts/api/library_upload_dir.py b/scripts/api/library_upload_dir.py
index 84d321d6fc4..421f2d1b072 100644
--- a/scripts/api/library_upload_dir.py
+++ b/scripts/api/library_upload_dir.py
@@ -8,7 +8,7 @@ import sys
 from bioblend import galaxy
 
 
-class Uploader:
+class Uploader(object):
 
     def __init__(self, url, api, library_id, folder_id, should_link,
                  non_local):
diff --git a/scripts/apply_tags.py b/scripts/apply_tags.py
index 1d118f19db0..e554d5b56ec 100644
--- a/scripts/apply_tags.py
+++ b/scripts/apply_tags.py
@@ -6,7 +6,7 @@ import time
 from bioblend.galaxy import GalaxyInstance
 
 
-class ApplyTagsHistory:
+class ApplyTagsHistory(object):
 
     @classmethod
     def __init__(self, galaxy_url, galaxy_api_key, history_id=None):
diff --git a/scripts/check_galaxy.py b/scripts/check_galaxy.py
index 6a6a8618015..22f96a6bf0c 100755
--- a/scripts/check_galaxy.py
+++ b/scripts/check_galaxy.py
@@ -107,7 +107,7 @@ tc.agent("Mozilla/5.0 (compatible; check_galaxy/0.1)")
 tc.config('use_tidy', 0)
 
 
-class Browser:
+class Browser(object):
 
     def __init__(self):
         self.server = server
diff --git a/scripts/grt/export.py b/scripts/grt/export.py
index 070eeef220b..5a8ee8c4c91 100644
--- a/scripts/grt/export.py
+++ b/scripts/grt/export.py
@@ -48,7 +48,7 @@ def kw_metrics(job):
     }
 
 
-class Sanitization:
+class Sanitization(object):
 
     def __init__(self, sanitization_config, model, sa_session):
         self.sanitization_config = sanitization_config
diff --git a/scripts/microbes/util.py b/scripts/microbes/util.py
index 55021f43480..1e4f7b3650c 100644
--- a/scripts/microbes/util.py
+++ b/scripts/microbes/util.py
@@ -7,7 +7,7 @@ assert sys.version_info[:2] >= (2, 4)
 
 
 # genbank_to_bed
-class Region:
+class Region(object):
     def __init__(self):
         self.qualifiers = {}
         self.start = None
@@ -37,7 +37,7 @@ class Region:
                     self.end = end
 
 
-class GenBankFeatureParser:
+class GenBankFeatureParser(object):
     """Parses Features from Single Locus GenBank file"""
     def __init__(self, fh, features_list=[]):
         self.fh = fh
diff --git a/test/base/api.py b/test/base/api.py
index 57b078ec83d..9ec0a7e44a2 100644
--- a/test/base/api.py
+++ b/test/base/api.py
@@ -19,7 +19,7 @@ from .interactor import TestCaseGalaxyInteractor as BaseInteractor
 from .testcase import FunctionalTestCase
 
 
-class UsesApiTestCaseMixin:
+class UsesApiTestCaseMixin(object):
 
     def _api_url(self, path, params=None, use_key=None, use_admin_key=None):
         if not params:
diff --git a/test/base/populators.py b/test/base/populators.py
index c3cc68e477e..ed0bb33a864 100644
--- a/test/base/populators.py
+++ b/test/base/populators.py
@@ -140,7 +140,7 @@ def _raise_skip_if(check):
 
 # Deprecated mixin, use dataset populator instead.
 # TODO: Rework existing tests to target DatasetPopulator in a setup method instead.
-class TestsDatasets:
+class TestsDatasets(object):
 
     def _new_dataset(self, history_id, content='TestData123', **kwds):
         return DatasetPopulator(self.galaxy_interactor).new_dataset(history_id, content=content, **kwds)
@@ -1087,7 +1087,7 @@ def wait_on_state(state_func, desc="state", skip_states=["running", "queued", "n
         raise TimeoutAssertionError("%s Current response containing state [%s]." % (str(e), response.json()))
 
 
-class GiPostGetMixin:
+class GiPostGetMixin(object):
     """Mixin for adapting Galaxy testing populators helpers to bioblend."""
 
     def _get(self, route, data={}):
diff --git a/test/galaxy_selenium/has_driver.py b/test/galaxy_selenium/has_driver.py
index 447ff3fd83d..0bdf77547a6 100644
--- a/test/galaxy_selenium/has_driver.py
+++ b/test/galaxy_selenium/has_driver.py
@@ -14,7 +14,7 @@ from selenium.webdriver.support.ui import WebDriverWait
 UNSPECIFIED_TIMEOUT = object()
 
 
-class HasDriver:
+class HasDriver(object):
     TimeoutException = TimeoutException
 
     def assert_xpath(self, xpath):
diff --git a/test/integration/test_job_environments.py b/test/integration/test_job_environments.py
index 7d2ef8cffa2..7ce81fc2e1a 100644
--- a/test/integration/test_job_environments.py
+++ b/test/integration/test_job_environments.py
@@ -24,7 +24,7 @@ JobEnviromentProperties = collections.namedtuple("JobEnvironmentProperties", [
 ])
 
 
-class RunsEnvironmentJobs:
+class RunsEnvironmentJobs(object):
 
     def _run_and_get_environment_properties(self, tool_id="job_environment_default"):
         with self.dataset_populator.test_history() as history_id:
diff --git a/test/selenium_tests/framework.py b/test/selenium_tests/framework.py
index 26c07fb0ec8..87569eda3ef 100644
--- a/test/selenium_tests/framework.py
+++ b/test/selenium_tests/framework.py
@@ -431,7 +431,7 @@ class SharedStateSeleniumTestCase(SeleniumTestCase):
         """Override this to setup shared data for tests that gets initialized only once."""
 
 
-class UsesHistoryItemAssertions:
+class UsesHistoryItemAssertions(object):
 
     def assert_item_peek_includes(self, hid, expected):
         item_body = self.history_panel_item_component(hid=hid)
@@ -508,7 +508,7 @@ def get_remote_driver():
     )
 
 
-class SeleniumSessionGetPostMixin:
+class SeleniumSessionGetPostMixin(object):
     """Mixin for adapting Galaxy testing populators helpers to Selenium session backed bioblend."""
 
     def _get(self, route, data={}):
diff --git a/tools/filters/join.py b/tools/filters/join.py
index e2094bc9b63..13f820199d3 100644
--- a/tools/filters/join.py
+++ b/tools/filters/join.py
@@ -20,7 +20,7 @@ from galaxy.util import stringify_dictionary_keys
 from galaxy.util.bunch import Bunch
 
 
-class OffsetList:
+class OffsetList(object):
     def __init__(self, filesize=0, fmt=None):
         self.file = tempfile.NamedTemporaryFile('w+b')
         if fmt:
@@ -146,7 +146,7 @@ class SortedOffsets(OffsetList):
 
 
 # indexed set of offsets, index is built on demand
-class OffsetIndex:
+class OffsetIndex(object):
     def __init__(self, filename, column, split=None, index_depth=3):
         self.filename = filename
         self.file = open(filename, 'r')
@@ -239,7 +239,7 @@ class OffsetIndex:
                 first_char = identifier[0]
 
 
-class BufferedIndex:
+class BufferedIndex(object):
     def __init__(self, filename, column, split=None, buffer=1000000, index_depth=3):
         self.index = OffsetIndex(filename, column, split, index_depth)
         self.buffered_offsets = {}
diff --git a/tools/filters/sff_extract.py b/tools/filters/sff_extract.py
index cfb0cb53afa..98620572776 100644
--- a/tools/filters/sff_extract.py
+++ b/tools/filters/sff_extract.py
@@ -1180,7 +1180,7 @@ def read_ssaha_data(ssahadata_fh):
 #
 ##########################################################################
 
-class Fasta:
+class Fasta(object):
     def __init__(self, name, sequence):
         self.name = name
         self.sequence = sequence
diff --git a/tools/phenotype_association/senatag.py b/tools/phenotype_association/senatag.py
index d4637838d2b..8a7a8c08dcd 100755
--- a/tools/phenotype_association/senatag.py
+++ b/tools/phenotype_association/senatag.py
@@ -37,7 +37,7 @@ debug_flag = False
 
 
 @total_ordering
-class node:
+class node(object):
     def __init__(self, name):
         self.name = name
         self.edges = []
@@ -65,7 +65,7 @@ class node:
         return self.name
 
 
-class graph:
+class graph(object):
     def __init__(self):
         self.nodes = {}
 
diff --git a/tools/stats/aggregate_scores_in_intervals.py b/tools/stats/aggregate_scores_in_intervals.py
index 704c4ae80d6..9c0cceba15b 100755
--- a/tools/stats/aggregate_scores_in_intervals.py
+++ b/tools/stats/aggregate_scores_in_intervals.py
@@ -25,7 +25,7 @@ from bx.cookbook import doc_optparse
 from galaxy.util.ucsc import UCSCLimitException, UCSCOutWrapper
 
 
-class PositionalScoresOnDisk:
+class PositionalScoresOnDisk(object):
     fmt = 'f'
     fmt_size = struct.calcsize(fmt)
     default_value = float('nan')