diff --git a/docs/source/config_files.rst b/docs/source/config_files.rst
index 8bbfc927..ae1fa3a5 100644
--- a/docs/source/config_files.rst
+++ b/docs/source/config_files.rst
@@ -29,7 +29,7 @@ can be found on this page (and to the right).
 that lets you install any kind of package,
 including Python, R, and C/C++ packages.
 ``repo2docker`` does not use your ``environment.yml`` to create and activate a new conda environment.
-Rather, it updates a base conda environment `defined here <https://github.com/jupyterhub/repo2docker/blob/master/repo2docker/buildpacks/conda/environment.yml>`_ with the packages listed in your ``environment.yml``.
+Rather, it updates a base conda environment `defined here <https://github.com/jupyterhub/repo2docker/blob/HEAD/repo2docker/buildpacks/conda/environment.yml>`_ with the packages listed in your ``environment.yml``.
 This means that the environment will always have the same default name, not the name
 specified in your ``environment.yml``.
 
diff --git a/docs/source/contributing/buildpack.md b/docs/source/contributing/buildpack.md
index 3d7d098b..556191c2 100644
--- a/docs/source/contributing/buildpack.md
+++ b/docs/source/contributing/buildpack.md
@@ -1,7 +1,7 @@
 # Add a new buildpack
 
 A new buildpack is needed when a new language or a new package manager should be
-supported. [Existing buildpacks](https://github.com/jupyterhub/repo2docker/tree/master/repo2docker/buildpacks)
+supported. [Existing buildpacks](https://github.com/jupyterhub/repo2docker/tree/HEAD/repo2docker/buildpacks)
 are a good model for how new buildpacks should be structured.
 See [the Buildpacks page](buildpacks) for more information about the
 structure of a buildpack.
diff --git a/docs/source/contributing/contentprovider.rst b/docs/source/contributing/contentprovider.rst
index 58ddba4b..df3c9147 100644
--- a/docs/source/contributing/contentprovider.rst
+++ b/docs/source/contributing/contentprovider.rst
@@ -5,7 +5,7 @@ Add a new content provider
 Adding a new content provider allows repo2docker to grab repositories from new
 locations on the internet. To do so, you should take the following steps:
 
-#. Sub-class the `ContentProvider class <https://github.com/jupyterhub/repo2docker/blob/master/repo2docker/contentproviders/base.py#L17>`_.
+#. Sub-class the `ContentProvider class <https://github.com/jupyterhub/repo2docker/blob/HEAD/repo2docker/contentproviders/base.py#L17>`_.
    This will give you a skeleton class you can modify to support your new
    content provider.
 #. Implement a **detect()** method for the class. This takes an input
diff --git a/docs/source/contributing/tasks.md b/docs/source/contributing/tasks.md
index 780033c7..49bb970f 100644
--- a/docs/source/contributing/tasks.md
+++ b/docs/source/contributing/tasks.md
@@ -52,8 +52,8 @@ To update one of the dependencies shared across all `repo2docker` builds, you
 must follow these steps (with more detailed information in the sections below):
 
 1. Make sure you have [Docker](https://www.docker.com/) running on your computer
-2. Bump the version numbers of the dependencies you want to update in the `conda` environment ([link](https://github.com/jupyterhub/repo2docker/blob/master/CONTRIBUTING.md#conda-dependencies))
-3. Make a pull request with your changes ([link](https://github.com/jupyterhub/repo2docker/blob/master/CONTRIBUTING.md#make-a-pull-request))
+2. Bump the version numbers of the dependencies you want to update in the `conda` environment ([link](https://github.com/jupyterhub/repo2docker/blob/HEAD/CONTRIBUTING.md#conda-dependencies))
+3. Make a pull request with your changes ([link](https://github.com/jupyterhub/repo2docker/blob/HEAD/CONTRIBUTING.md#make-a-pull-request))
 
 See the subsections below for more detailed instructions.
 
diff --git a/docs/source/faq.rst b/docs/source/faq.rst
index 8fbc8ecc..50e35276 100644
--- a/docs/source/faq.rst
+++ b/docs/source/faq.rst
@@ -28,7 +28,7 @@ Repo2docker officially supports the following versions of Python
 - 2.7
 
 Additional versions may work, as long as the
-`base environment <https://github.com/jupyterhub/repo2docker/blob/master/repo2docker/buildpacks/conda/environment.yml>`_
+`base environment <https://github.com/jupyterhub/repo2docker/blob/HEAD/repo2docker/buildpacks/conda/environment.yml>`_
 can be installed for your version of Python.
 The most likely source of incompatibility is if one of the packages
 in the base environment is not packaged for your Python,
diff --git a/docs/source/index.rst b/docs/source/index.rst
index 363488d2..09be2503 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -19,7 +19,7 @@ to build images on demand.
 
 Please report `Bugs <https://github.com/jupyterhub/repo2docker/issues>`_,
 `ask questions <https://gitter.im/jupyterhub/binder>`_ or
-`contribute to the project <https://github.com/jupyterhub/repo2docker/blob/master/CONTRIBUTING.md>`_.
+`contribute to the project <https://github.com/jupyterhub/repo2docker/blob/HEAD/CONTRIBUTING.md>`_.
 
 .. toctree::
    :maxdepth: 2
diff --git a/docs/source/install.rst b/docs/source/install.rst
index 09aff8f2..e8fea2c9 100644
--- a/docs/source/install.rst
+++ b/docs/source/install.rst
@@ -19,7 +19,7 @@ The latest version of Docker, ``18.03``, successfully builds repositories from
 `binder-examples <https://github.com/binder-examples>`_.
 The `BinderHub <https://binderhub.readthedocs.io/>`_ helm chart uses version
 ``17.11.0-ce-dind``.  See the
-`helm chart <https://github.com/jupyterhub/binderhub/blob/master/helm-chart/binderhub/values.yaml#L167>`_
+`helm chart <https://github.com/jupyterhub/binderhub/blob/HEAD/helm-chart/binderhub/values.yaml#L167>`_
 for more details.
 
 Optional: Mercurial