diff --git a/README.md b/README.md
index 504906b..1442448 100644
--- a/README.md
+++ b/README.md
@@ -119,4 +119,22 @@ users:
       privilege: ['create', 'read', 'update', 'delete', 'upload']   
 ```
 
-Refer to [Setting up Users](#Setting-Up-Users) to review how to apply the changes made in the `user.yaml` file to the database
\ No newline at end of file
+Refer to [Setting up Users](#Setting-Up-Users) to review how to apply the changes made in the `user.yaml` file to the database
+
+### Changing the data dictionary
+The data dictionary the commons uses is dictated by the `DICTIONARY_URL` environment variable in both sheepdog and peregrine. The default value for this variable is set to `https://s3.amazonaws.com/dictionary-artifacts/datadictionary/develop/schema.json`, which is the developer test data dictionary. To override this default, edit the `environment` fields in the peregrine sections of the `docker-compose.yml` file. This will change the value of the environment variable in both sheepdog and peregrine. An example, where the `DICTIONARY_URL` environment variable is set to the url of the dev data dictionary, is provided in the docker-compose.yml. Another example is shown below:
+```
+peregrine:
+  image: "quay.io/cdis/peregrine:master"
+  command: bash /peregrine_setup.sh
+  .
+  .
+  .
+  environment: &env
+    DICTIONARY_URL: {YOUR_DICTIONARY_URL_GOES_HERE}
+  depends_on:
+    - postgres
+```
+In addition to changing the `DICTIONARY_URL` field, it may also be necesary to change the `APP` environment variable in data-portal. This will only be the case if the alternate dictionary deviates too much from the default dev dictionary.
+
+As this is a change to the Docker Compose configuration, you will need to restart the Docker Compose to apply the changes.
\ No newline at end of file
diff --git a/docker-compose.yml b/docker-compose.yml
index a39697a..4027294 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -40,7 +40,8 @@ services:
       - ./apis_configs/config_helper.py:/var/www/peregrine/config_helper.py 
       - ./temp_creds/service.crt:/usr/local/share/ca-certificates/cdis-ca.crt
       - ./scripts/peregrine_setup.sh:/peregrine_setup.sh
-    environment:
+    environment: &env
+      DICTIONARY_URL: https://s3.amazonaws.com/dictionary-artifacts/datadictionary/develop/schema.json
       REQUESTS_CA_BUNDLE: /etc/ssl/certs/ca-certificates.crt
     depends_on:
       - postgres
@@ -54,6 +55,7 @@ services:
       - ./apis_configs/sheepdog_creds.json:/var/www/sheepdog/creds.json
       - ./apis_configs/config_helper.py:/var/www/sheepdog/config_helper.py 
       - ./scripts/sheepdog_setup.sh:/sheepdog_setup.sh
+    environment: *env
     depends_on:
       - postgres
   dataportal: