diff --git a/test/functional/PIMemberRequestTest.php b/test/functional/PIMemberRequestTest.php
index 71072fef..4d8a41fa 100644
--- a/test/functional/PIMemberRequestTest.php
+++ b/test/functional/PIMemberRequestTest.php
@@ -10,6 +10,7 @@ private function requestMembership(string $gid_or_mail)
         http_post(__DIR__ . "/../../webroot/panel/groups.php", [
             "form_type" => "addPIform",
             "pi" => $gid_or_mail,
+            "tos" => "agree",
         ]);
     }
 
diff --git a/test/functional/PiMemberApproveTest.php b/test/functional/PiMemberApproveTest.php
index 4d74c103..b59643b7 100644
--- a/test/functional/PiMemberApproveTest.php
+++ b/test/functional/PiMemberApproveTest.php
@@ -34,6 +34,7 @@ private function requestJoinPI(string $gid)
         http_post(__DIR__ . "/../../webroot/panel/groups.php", [
             "form_type" => "addPIform",
             "pi" => $gid,
+            "tos" => "agree",
         ]);
     }
 
diff --git a/webroot/panel/groups.php b/webroot/panel/groups.php
index 37f6d526..d13327a0 100644
--- a/webroot/panel/groups.php
+++ b/webroot/panel/groups.php
@@ -26,6 +26,9 @@
 
         switch ($_POST["form_type"]) {
             case "addPIform":
+                if (!isset($_POST["tos"]) || $_POST["tos"] != "agree") {
+                    UnityHTTPD::badRequest("user did not agree to terms of service");
+                }
                 if ($pi_account->exists()) {
                     if ($pi_account->requestExists($USER)) {
                         array_push($modalErrors, "You've already requested this");
diff --git a/webroot/panel/modal/new_pi.php b/webroot/panel/modal/new_pi.php
index 53368e96..14d486f6 100644
--- a/webroot/panel/modal/new_pi.php
+++ b/webroot/panel/modal/new_pi.php
@@ -13,6 +13,13 @@
         <input type="text" id="pi_search" name="pi" placeholder="Search PI by NetID" required>
         <div class="searchWrapper" style="display: none;"></div>
     </div>
+    <label>
+        <input type='checkbox' name='tos' value='agree' required>
+        I have read and accept the
+        <a href='<?php echo CONFIG["site"]["terms_of_service_url"]; ?>' target='_blank'>
+            Terms of Service
+        </a>.
+    </label>
     <input type="submit" value="Send Request">
 </form>