diff --git a/.travis.yml b/.travis.yml
index 1bc0c44..7a59294 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@ branches:
   # (Builds will *also* still run on pull requests;
   # this avoids duplicate builds on the PR *branches*, too.)
   only:
-    - master
+    - main
     - /^v\d+\.\d+(\.(\d|x)+)?(-\S*)?$/
 
 env:
diff --git a/README.rst b/README.rst
index 12bb418..7d92cae 100644
--- a/README.rst
+++ b/README.rst
@@ -51,7 +51,7 @@ The package is released under the BSD license.
 
 .. END shared-intro
 
-.. image:: https://travis-ci.org/anymail/django-anymail.svg?branch=master
+.. image:: https://travis-ci.org/anymail/django-anymail.svg?branch=main
        :target: https://travis-ci.org/anymail/django-anymail
        :alt:    build status on Travis-CI
 
diff --git a/docs/_static/version-alert.js b/docs/_static/version-alert.js
index 7897c70..6183307 100644
--- a/docs/_static/version-alert.js
+++ b/docs/_static/version-alert.js
@@ -1,7 +1,7 @@
 "use strict";
 
-// Similar to https://github.com/rtfd/readthedocs.org/blob/master/readthedocs/core/static-src/core/js/doc-embed/version-compare.js
-// but adds admonition for the "latest" version -- which is (unreleased) master branch.
+// Similar to https://github.com/readthedocs/readthedocs.org/blob/5.2.3/readthedocs/core/static-src/core/js/doc-embed/version-compare.js
+// but adds admonition for the "latest" version -- which is (unreleased) main branch.
 
 function warnOnLatestVersion() {
 
diff --git a/docs/contributing.rst b/docs/contributing.rst
index 544fc89..aaf45a9 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -26,7 +26,7 @@ improve Anymail.
 Anymail evolved from the `Djrill`_ project. Special thanks to the
 folks from `brack3t`_ who developed the original version of Djrill.
 
-.. _AUTHORS.txt: https://github.com/anymail/django-anymail/blob/master/AUTHORS.txt
+.. _AUTHORS.txt: https://github.com/anymail/django-anymail/blob/main/AUTHORS.txt
 .. _brack3t: http://brack3t.com/
 .. _Djrill: https://github.com/brack3t/Djrill
 
@@ -133,8 +133,8 @@ for all 20+ supported combinations of Python and Django, sending hundreds of mes
 
 .. _pyenv: https://github.com/pyenv/pyenv
 .. _tested on Travis CI: https://travis-ci.org/anymail/django-anymail
-.. _tests source: https://github.com/anymail/django-anymail/blob/master/tests
-.. _.travis.yml: https://github.com/anymail/django-anymail/blob/master/.travis.yml
+.. _tests source: https://github.com/anymail/django-anymail/blob/main/tests
+.. _.travis.yml: https://github.com/anymail/django-anymail/blob/main/.travis.yml
 
 
 Documentation
diff --git a/docs/esps/mailjet.rst b/docs/esps/mailjet.rst
index 280941b..4b35b53 100644
--- a/docs/esps/mailjet.rst
+++ b/docs/esps/mailjet.rst
@@ -55,7 +55,7 @@ under `API Key Management`_. (Mailjet's documentation also sometimes uses
           "MAILJET_SECRET_KEY": "<your API secret>",
       }
 
-You can use either a master or sub-account API key.
+You can use either the main account or a sub-account API key.
 
 Anymail will also look for ``MAILJET_API_KEY`` and ``MAILJET_SECRET_KEY`` at the
 root of the settings file if neither ``ANYMAIL["MAILJET_API_KEY"]``
diff --git a/setup.py b/setup.py
index 5257558..a1f70e9 100644
--- a/setup.py
+++ b/setup.py
@@ -19,7 +19,7 @@ with open(path.join(here, "anymail/_version.py"), encoding='utf-8') as f:
 def long_description_from_readme(rst):
     # Freeze external links (on PyPI) to refer to this X.Y or X.Y.Z tag.
     # (This relies on tagging releases with 'vX.Y' or 'vX.Y.Z' in GitHub.)
-    rst = re.sub(r'(?<=branch=)master'     # Travis build status: branch=master --> branch=vX.Y.Z
+    rst = re.sub(r'(?<=branch=)main'       # Travis build status: branch=main --> branch=vX.Y.Z
                  r'|(?<=/)stable'          # ReadTheDocs links: /stable --> /vX.Y.Z
                  r'|(?<=version=)stable',  # ReadTheDocs badge: version=stable --> version=vX.Y.Z
                  release_tag, rst)  # (?<=...) is "positive lookbehind": must be there, but won't get replaced
diff --git a/tests/test_sendinblue_integration.py b/tests/test_sendinblue_integration.py
index 1375931..50e6641 100644
--- a/tests/test_sendinblue_integration.py
+++ b/tests/test_sendinblue_integration.py
@@ -99,7 +99,7 @@ class SendinBlueBackendIntegrationTests(AnymailTestMixin, SimpleTestCase):
             'attachment': [{
                 'name': 'attachment1.txt',
                 # URL where Sendinblue can download the attachment content while sending:
-                'url': 'https://raw.githubusercontent.com/anymail/django-anymail/master/AUTHORS.txt',
+                'url': 'https://raw.githubusercontent.com/anymail/django-anymail/main/AUTHORS.txt',
             }]
         }