diff --git a/ccvpn/context_processors.py b/ccvpn/context_processors.py
index 365bf54..e8c45f9 100644
--- a/ccvpn/context_processors.py
+++ b/ccvpn/context_processors.py
@@ -12,4 +12,5 @@ def some_settings(request):
         'ADDITIONAL_HTML': settings.ADDITIONAL_HTML,
         'SUPPORT_TEMPLATE': settings.SUPPORT_TEMPLATE,
         'ADDITIONAL_HEADER_HTML': settings.ADDITIONAL_HEADER_HTML,
+        'HCAPTCHA_SITE_KEY': settings.HCAPTCHA_SITE_KEY,
     }
diff --git a/lambdainst/views.py b/lambdainst/views.py
index 34604b0..246236c 100644
--- a/lambdainst/views.py
+++ b/lambdainst/views.py
@@ -71,6 +71,13 @@ def signup(request):
 
     form = SignupForm(request.POST)
 
+    grr = request.POST.get('g-recaptcha-response', '')
+    if captcha_test(grr, request):
+        request.session['signup_captcha_pass'] = True
+    elif not request.session.get('signup_captcha_pass'):
+        messages.error(request, _("Invalid captcha. Please try again"))
+        return render(request, 'ccvpn/signup.html', dict(form=form))
+
     if not form.is_valid():
         return render(request, 'ccvpn/signup.html', dict(form=form))
 
@@ -92,6 +99,9 @@ def signup(request):
     user.backend = 'django.contrib.auth.backends.ModelBackend'
     auth.login(request, user)
 
+    # invalidate that captcha
+    request.session['signup_captcha_pass'] = False
+
     return redirect('account:index')
 
 
diff --git a/templates/ccvpn/signup.html b/templates/ccvpn/signup.html
index 998ac04..1b6ffee 100644
--- a/templates/ccvpn/signup.html
+++ b/templates/ccvpn/signup.html
@@ -34,6 +34,11 @@
                 {% trans 'Used to recover your password and confirm stuff.' %}
             </p>
 
+            {% if not request.session.signup_captcha_pass %}
+            <div class="h-captcha" data-sitekey="{{ HCAPTCHA_SITE_KEY }}" data-callback="onCaptcha"></div>
+            <script src="https://hcaptcha.com/1/api.js" async defer></script>
+            {% endif %}
+
             <input type="submit" class="pure-button pure-button-primary" value="{% trans 'Sign up' %}" />
         </form>
         <div class="rightsignup links">