diff --git a/md_pdf/config/validate.py b/md_pdf/config/validate.py
index a9d5623..22e20cf 100644
--- a/md_pdf/config/validate.py
+++ b/md_pdf/config/validate.py
@@ -69,12 +69,20 @@ def validate_context(config):
         raise ConfigValidationException("Context keys must be plain. Invalid values: {}".format(", ".join(invalid_values)))
 
 
+def validate_toc(config):
+    if 'toc' not in config:
+        return
+    if type(config['toc']) != bool:
+        raise ConfigValidationException("Table of contents key should be either true or false")
+
+
 def validate_config(config):
     for validator in [
         check_required_keys,
         test_input,
         test_output,
         validate_bibliography,
-        validate_context
+        validate_context,
+        validate_toc
     ]:
         validator(config)
diff --git a/test-files/mdp.yml b/test-files/mdp.yml
index 411e971..661ce22 100644
--- a/test-files/mdp.yml
+++ b/test-files/mdp.yml
@@ -12,3 +12,4 @@ context:
   student_number: 123456
   turnitin_number: 789123
 title: test title
+toc: true