diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 696eb8aee1256..ff8d7d3799497 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -4,7 +4,7 @@
 
 <!--
 Checklist:
-- Read the [Contributing Guidelines](https://github.com/python/mypy/blob/master/CONTRIBUTING.md)
+- Read the [Contributing Guidelines](https://github.com/python/mypy/blob/main/CONTRIBUTING.md)
 - Add tests for all changed behaviour.
 - If you can't add a test, please explain why and how you verified your changes work.
 - Make sure CI passes.
diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index da140375d603b..31bf72a1e852d 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -2,7 +2,7 @@ name: Trigger wheel build
 
 on:
   push:
-    branches: [main, master, 'release*']
+    branches: [main, 'release*']
     tags: ['*']
 
 jobs:
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index 8851f7fbb0f38..f5d80aec33c39 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -3,7 +3,7 @@ name: Check documentation build
 on:
   workflow_dispatch:
   push:
-    branches: [main, master, 'release*']
+    branches: [main, 'release*']
     tags: ['*']
   pull_request:
     paths:
diff --git a/.github/workflows/mypy_primer.yml b/.github/workflows/mypy_primer.yml
index e7e4af1f07b7e..cad3b25a187c3 100644
--- a/.github/workflows/mypy_primer.yml
+++ b/.github/workflows/mypy_primer.yml
@@ -1,7 +1,7 @@
 name: Run mypy_primer
 
 on:
-  # Only run on PR, since we diff against master
+  # Only run on PR, since we diff against main
   pull_request:
     paths-ignore:
     - 'docs/**'
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 81587f3ca7476..4667a284f3d24 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -3,7 +3,7 @@ name: Tests
 on:
   workflow_dispatch:
   push:
-    branches: [main, master, 'release*']
+    branches: [main, 'release*']
     tags: ['*']
   pull_request:
     paths-ignore:
diff --git a/.github/workflows/test_stubgenc.yml b/.github/workflows/test_stubgenc.yml
index db9bf413faa36..19d72bd6b321c 100644
--- a/.github/workflows/test_stubgenc.yml
+++ b/.github/workflows/test_stubgenc.yml
@@ -3,7 +3,7 @@ name: Test stubgenc on pybind11-mypy-demo
 on:
   workflow_dispatch:
   push:
-    branches: [main, master, 'release*']
+    branches: [main, 'release*']
     tags: ['*']
   pull_request:
     paths:
diff --git a/CREDITS b/CREDITS
index fb2fe155a9b89..120e67d9c1ef5 100644
--- a/CREDITS
+++ b/CREDITS
@@ -2,7 +2,7 @@ Credits
 -------
 
 For a full list of contributors you can mine the commit history:
-https://github.com/python/mypy/commits/master
+https://github.com/python/mypy/commits/main
 
 For lists of contributors per mypy release (including typeshed) see
 the release blog posts at https://mypy-lang.blogspot.com/.
diff --git a/README.md b/README.md
index 164957b1491a1..1f1e40fa2b517 100644
--- a/README.md
+++ b/README.md
@@ -102,7 +102,7 @@ repo directly:
 ```bash
 python3 -m pip install -U git+https://github.com/python/mypy.git
 # or if you don't have 'git' installed
-python3 -m pip install -U https://github.com/python/mypy/zipball/master
+python3 -m pip install -U https://github.com/python/mypy/zipball/main
 ```
 
 Now you can type-check the [statically typed parts] of a program like this:
diff --git a/docs/source/additional_features.rst b/docs/source/additional_features.rst
index 10122e9b2fa9a..6a4740d5a96ef 100644
--- a/docs/source/additional_features.rst
+++ b/docs/source/additional_features.rst
@@ -247,7 +247,7 @@ Your CI script might work like this:
 
 * Create a tarball from the ``.mypy_cache`` directory.
 
-* Determine the current git master branch commit id (say, using
+* Determine the current git main branch commit id (say, using
   ``git rev-parse HEAD``).
 
 * Upload the tarball to the shared repository with a name derived from the
@@ -262,13 +262,13 @@ populates the local ``.mypy_cache`` directory from the shared
 repository and then runs a normal incremental build.
 
 The wrapper script needs some logic to determine the most recent
-central repository commit (by convention, the ``origin/master`` branch
+central repository commit (by convention, the ``origin/main`` branch
 for git) the local development branch is based on. In a typical git
 setup you can do it like this:
 
 .. code::
 
-    git merge-base HEAD origin/master
+    git merge-base HEAD origin/main
 
 The next step is to download the cache data (contents of the
 ``.mypy_cache`` directory) from the shared repository based on the
@@ -315,11 +315,11 @@ at least if your codebase is hundreds of thousands of lines or more:
   potentially large number of changes in an incremental build, as this can
   be much slower than downloading cache data and restarting the daemon.
 
-* If the current local branch is based on a very recent master commit,
+* If the current local branch is based on a very recent main commit,
   the remote cache data may not yet be available for that commit, as
   there will necessarily be some latency to build the cache files. It
   may be a good idea to look for cache data for, say, the 5 latest
-  master commits and use the most recent data that is available.
+  main commits and use the most recent data that is available.
 
 * If the remote cache is not accessible for some reason (say, from a public
   network), the script can still fall back to a normal incremental build.
diff --git a/docs/source/extending_mypy.rst b/docs/source/extending_mypy.rst
index daf8636163344..9595c81efca77 100644
--- a/docs/source/extending_mypy.rst
+++ b/docs/source/extending_mypy.rst
@@ -93,9 +93,9 @@ can be specified after colon:
 
 In the following sections we describe the basics of the plugin system with
 some examples. For more technical details, please read the docstrings in
-`mypy/plugin.py <https://github.com/python/mypy/blob/master/mypy/plugin.py>`_
+`mypy/plugin.py <https://github.com/python/mypy/blob/main/mypy/plugin.py>`_
 in mypy source code. Also you can find good examples in the bundled plugins
-located in `mypy/plugins <https://github.com/python/mypy/tree/master/mypy/plugins>`_.
+located in `mypy/plugins <https://github.com/python/mypy/tree/main/mypy/plugins>`_.
 
 High-level overview
 *******************
diff --git a/docs/source/index.rst b/docs/source/index.rst
index c9dc6bc1f8c99..7528372eae48f 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -1,4 +1,4 @@
-.. Mypy documentation master file, created by
+.. Mypy documentation main file, created by
    sphinx-quickstart on Sun Sep 14 19:50:35 2014.
    You can adapt this file completely to your liking, but it should at least
    contain the root `toctree` directive.
diff --git a/misc/perf_compare.py b/misc/perf_compare.py
index be05bb6ddc32a..1d292488d1a5a 100644
--- a/misc/perf_compare.py
+++ b/misc/perf_compare.py
@@ -2,7 +2,7 @@
 
 Simple usage:
 
-  python misc/perf_compare.py my-branch master ...
+  python misc/perf_compare.py my-branch main ...
 
 What this does:
 
diff --git a/misc/trigger_wheel_build.sh b/misc/trigger_wheel_build.sh
index c914a6e7cf867..f4874749f9021 100755
--- a/misc/trigger_wheel_build.sh
+++ b/misc/trigger_wheel_build.sh
@@ -19,5 +19,5 @@ cd build
 echo $COMMIT > mypy_commit
 git commit -am "Build wheels for mypy $V"
 git tag v$V
-# Push a tag, but no need to push the change to master
+# Push a tag, but no need to push the change to main
 git push --tags
diff --git a/mypy/errors.py b/mypy/errors.py
index 9d29259e943c1..edcf6dbdbc22a 100644
--- a/mypy/errors.py
+++ b/mypy/errors.py
@@ -1150,7 +1150,7 @@ def report_internal_error(
     # Print "INTERNAL ERROR" message.
     print(
         f"{prefix}error: INTERNAL ERROR --",
-        "Please try using mypy master on GitHub:\n"
+        "Please try using mypy main on GitHub:\n"
         "https://mypy.readthedocs.io/en/stable/common_issues.html"
         "#using-a-development-mypy-build",
         file=stderr,
@@ -1159,7 +1159,7 @@ def report_internal_error(
         print("Please report a bug at https://github.com/python/mypy/issues", file=stderr)
     else:
         print(
-            "If this issue continues with mypy master, "
+            "If this issue continues with mypy main, "
             "please report a bug at https://github.com/python/mypy/issues",
             file=stderr,
         )
diff --git a/mypyc/doc/dev-intro.md b/mypyc/doc/dev-intro.md
index d11df7068e91c..9c204588cc0e3 100644
--- a/mypyc/doc/dev-intro.md
+++ b/mypyc/doc/dev-intro.md
@@ -63,7 +63,7 @@ features.
 ## Development Environment
 
 First you should set up the mypy development environment as described in
-the [mypy docs](https://github.com/python/mypy/blob/master/README.md).
+the [mypy docs](https://github.com/python/mypy/blob/main/README.md).
 macOS, Linux and Windows are supported.
 
 ## Compiling and Running Programs
diff --git a/mypyc/doc/index.rst b/mypyc/doc/index.rst
index 5b1cc48fab3d1..c3edcdf24f624 100644
--- a/mypyc/doc/index.rst
+++ b/mypyc/doc/index.rst
@@ -1,4 +1,4 @@
-.. mypyc documentation master file, created by
+.. mypyc documentation main file, created by
    sphinx-quickstart on Sun Apr  5 14:01:55 2020.
    You can adapt this file completely to your liking, but it should at least
    contain the root `toctree` directive.