diff --git a/bedevere/backport.py b/bedevere/backport.py
index 10c17e8f..5f559432 100644
--- a/bedevere/backport.py
+++ b/bedevere/backport.py
@@ -84,7 +84,7 @@ async def validate_maintenance_branch_pr(event, gh, *args, **kwargs):
     pull_request = event.data["pull_request"]
     base_branch = pull_request["base"]["ref"]
 
-    if base_branch == "master":
+    if base_branch == "main":
         return
 
     title = util.normalize_title(pull_request["title"],
diff --git a/bedevere/close_pr.py b/bedevere/close_pr.py
index 4827c5fb..b09adc58 100644
--- a/bedevere/close_pr.py
+++ b/bedevere/close_pr.py
@@ -1,4 +1,4 @@
-"""Automatically close PR that tries to merge maintenance branch into master."""
+"""Automatically close PR that tries to merge maintenance branch into main."""
 import re
 
 import gidgethub.routing
@@ -8,7 +8,7 @@
 
 INVALID_PR_COMMENT = """\
 PRs attempting to merge a maintenance branch into the \
-master branch are deemed to be spam and automatically closed. \
+main branch are deemed to be spam and automatically closed. \
 If you were attempting to report a bug, please go to bugs.python.org; \
 see devguide.python.org for further instruction as needed."""
 
@@ -21,14 +21,14 @@ async def close_invalid_pr(event, gh, *args, **kwargs):
     """Close the invalid PR, add 'invalid' label, and post a message.
 
     PR is considered invalid if:
-    * base_label is 'python:master'
+    * base_label is 'python:main'
     * head_label is '<username>:<maint_branch>'
     """
     head_label = event.data["pull_request"]["head"]["label"]
     base_label = event.data["pull_request"]["base"]["label"]
 
     if PYTHON_MAINT_BRANCH_RE.match(head_label) and \
-        base_label == "python:master":
+        base_label == "python:main":
         data = {'state': 'closed'}
         await gh.patch(event.data["pull_request"]["url"], data=data)
         await gh.post(
@@ -46,14 +46,14 @@ async def dismiss_invalid_pr_review_request(event, gh, *args, **kwargs):
     """Dismiss review request from the invalid PR.
 
     PR is considered invalid if:
-    * base_label is 'python:master'
+    * base_label is 'python:main'
     * head_label is '<username>:<maint_branch>'
     """
     head_label = event.data["pull_request"]["head"]["label"]
     base_label = event.data["pull_request"]["base"]["label"]
 
     if PYTHON_MAINT_BRANCH_RE.match(head_label) and \
-            base_label == "python:master":
+            base_label == "python:main":
         data = {"reviewers": [reviewer["login"] for reviewer in event.data["pull_request"]["requested_reviewers"]],
                 "team_reviewers": [team["name"] for team in event.data["pull_request"]["requested_teams"]]
                 }
diff --git a/tests/test_backport.py b/tests/test_backport.py
index 69f64f34..b20e03a7 100644
--- a/tests/test_backport.py
+++ b/tests/test_backport.py
@@ -329,7 +329,7 @@ async def test_not_valid_maintenance_branch_pr_title(action):
 
 
 @pytest.mark.parametrize('action', ['opened', 'reopened', 'edited', 'synchronize'])
-async def test_maintenance_branch_pr_status_not_posted_on_master(action):
+async def test_maintenance_branch_pr_status_not_posted_on_main(action):
     title = 'Fix some typo'
     data = {
         'action': action,
@@ -339,7 +339,7 @@ async def test_maintenance_branch_pr_status_not_posted_on_master(action):
             'body': '',
             'issue_url': 'https://api.github.com/issue/2248',
             'base': {
-                'ref': 'master',
+                'ref': 'main',
             },
             'statuses_url': 'https://api.github.com/repos/python/cpython/statuses/somehash',
         },
diff --git a/tests/test_close_pr.py b/tests/test_close_pr.py
index b8778345..842fe3f6 100644
--- a/tests/test_close_pr.py
+++ b/tests/test_close_pr.py
@@ -45,7 +45,7 @@ async def test_close_invalid_pr_on_open():
                 "label": "python:3.6"
             },
             "base": {
-                "label": "python:master"
+                "label": "python:main"
             }
         },
     }
@@ -80,7 +80,7 @@ async def test_close_invalid_pr_on_synchronize():
                 "label": "python:3.6"
             },
             "base": {
-                "label": "python:master"
+                "label": "python:main"
             }
         },
     }
@@ -115,7 +115,7 @@ async def test_valid_pr_not_closed():
                 "label": "someuser:bpo-3.6"
             },
             "base": {
-                "label": "python:master"
+                "label": "python:main"
             }
         },
     }
@@ -144,7 +144,7 @@ async def test_close_invalid_pr_on_open_not_python_as_head():
                 "label": "username123:3.6"
             },
             "base": {
-                "label": "python:master"
+                "label": "python:main"
             }
         },
     }
@@ -173,7 +173,7 @@ async def test_pr_with_head_branch_containing_all_digits_not_closed():
                 "label": "someuser:12345"
             },
             "base": {
-                "label": "python:master"
+                "label": "python:main"
             }
         },
     }
@@ -203,7 +203,7 @@ async def test_dismiss_review_request_for_invalid_pr():
                 "label": "python:3.6"
             },
             "base": {
-                "label": "python:master"
+                "label": "python:main"
             },
             "requested_reviewers": [
                 {
@@ -246,7 +246,7 @@ async def test_valid_pr_review_request_not_dismissed():
                 "label": "someuser:bpo-3.6"
             },
             "base": {
-                "label": "python:master"
+                "label": "python:main"
             },
             "requested_reviewers": [
                 {