diff --git a/app/try_ruby.rb b/app/try_ruby.rb
index f3b93ca..bab28bb 100644
--- a/app/try_ruby.rb
+++ b/app/try_ruby.rb
@@ -381,6 +381,10 @@ def update_screen(item)
     step = item.step.to_s
     $document.at_css("#tryruby-index").value  = step
 
+    # Disable the buttons that have no step to go to
+    $document.at_css('#btn_back').disabled = !@items.has_key?(item.step - 1)
+    $document.at_css('#btn_next').disabled = !@items.has_key?(item.step + 1)
+
     # Set session cookie to store progress
     set_cookie('tryruby_step', step)
 
diff --git a/source/stylesheets/application.css.scss b/source/stylesheets/application.css.scss
index 0a88d6b..63e22fa 100644
--- a/source/stylesheets/application.css.scss
+++ b/source/stylesheets/application.css.scss
@@ -119,9 +119,13 @@ h3 {
 .btn-primary {
   border-radius: 1rem;
   font-family: sans-serif;
-  color: var(--button-primary-text-color);
-  background-color: var(--button-primary-color);
-  border-color: var(--button-primary-color);
+
+  &,
+  &:disabled {
+    color: var(--button-primary-text-color);
+    background-color: var(--button-primary-color);
+    border-color: var(--button-primary-color);
+  }
 
   &:focus,
   &:focus:not(:focus-visible),
diff --git a/spec/tutorial_spec.rb b/spec/tutorial_spec.rb
index 13d67e0..7bf89b2 100644
--- a/spec/tutorial_spec.rb
+++ b/spec/tutorial_spec.rb
@@ -50,6 +50,8 @@
           special = steps[step] || {}
 
           find(:css, "h1").text.should be == data["title"]
+          page.should have_button("Back", disabled: step == 1)
+          page.should have_button("Next", disabled: step == 56)
 
           unless special[:pass]
             case special[:code]