diff --git a/src/constants.ts b/src/constants.ts
index ab1035a..d9aee04 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -22,6 +22,7 @@ export const DEPARTMENTS = {
   "21H":   "History",
   "21L":   "Literature",
   "21M":   "Music and Theater Arts",
+  "21T":   "Theater Arts",
   22:      "Nuclear Science and Engineering",
   24:      "Linguistics and Philosophy",
   CC:      "Concourse",
diff --git a/src/hooks/validation.ts b/src/hooks/validation.ts
index bc01be7..29a9d4f 100644
--- a/src/hooks/validation.ts
+++ b/src/hooks/validation.ts
@@ -45,9 +45,16 @@ type QueryParamValidators<ReqParams> = {
   [k in keyof Required<ReqParams>]: (v: string[]) => ReqParams[k]
 }
 
+// "21T" (Theater Arts) isn't in the published mit-learn-api-axios DepartmentEnum yet,
+// so it's added here and cast to the enum value type. Remove once the openapi release ships.
+const PATCHED_DEPARTMENT_VALUES = [
+  ...Object.values(DepartmentEnum),
+  "21T"
+] as (typeof DepartmentEnum)[keyof typeof DepartmentEnum][]
+
 const resourceSearchValidators: QueryParamValidators<ResourceSearchRequest> = {
   resource_type:              withinEnum(Object.values(ResourceTypeEnum)),
-  department:                 withinEnum(Object.values(DepartmentEnum)),
+  department:                 withinEnum(Object.values(PATCHED_DEPARTMENT_VALUES)),
   level:                      withinEnum(Object.values(LevelEnum)),
   platform:                   withinEnum(Object.values(PlatformEnum)),
   offered_by:                 withinEnum(Object.values(OfferedByEnum)),