diff --git a/borgmatic/borg/environment.py b/borgmatic/borg/environment.py
index a37c1b5..490c07a 100644
--- a/borgmatic/borg/environment.py
+++ b/borgmatic/borg/environment.py
@@ -9,6 +9,7 @@ OPTION_TO_ENVIRONMENT_VARIABLE = {
     'encryption_passcommand': 'BORG_PASSCOMMAND',
     'encryption_passphrase': 'BORG_PASSPHRASE',
     'ssh_command': 'BORG_RSH',
+    'temporary_directory': 'TMPDIR',
 }
 
 DEFAULT_BOOL_OPTION_TO_ENVIRONMENT_VARIABLE = {
diff --git a/borgmatic/config/schema.yaml b/borgmatic/config/schema.yaml
index a45e867..511e3ce 100644
--- a/borgmatic/config/schema.yaml
+++ b/borgmatic/config/schema.yaml
@@ -228,6 +228,12 @@ map:
                     Remote network upload rate limit in kiBytes/second. Defaults
                     to unlimited.
                 example: 100
+            temporary_directory:
+                type: str
+                desc: |
+                    Directory where temporary files are stored. Defaults to
+                    $TMPDIR
+                example: /path/to/tmpdir
             ssh_command:
                 type: str
                 desc: |