diff --git a/typed-racket-lib/typed-racket/base-env/base-env.rkt b/typed-racket-lib/typed-racket/base-env/base-env.rkt
index b0d4ec9e..f8de6bd8 100644
--- a/typed-racket-lib/typed-racket/base-env/base-env.rkt
+++ b/typed-racket-lib/typed-racket/base-env/base-env.rkt
@@ -1390,8 +1390,18 @@
 [semaphore-wait/enable-break (-> -Semaphore -Void)]
 [semaphore-peek-evt (-> -Semaphore (-mu x (-evt x)))]
 [semaphore-peek-evt? (asym-pred Univ B (-FS (-filter (-mu x (-evt x)) 0) -top))]
-;[call-with-semaphore ???]
-;[call-with-semaphore/enable-break ???]
+[call-with-semaphore
+ (-polydots (b a)
+   (cl->* (->... (list -Semaphore (->... '() [a a] b))
+                 [a a] b)
+          (->... (list -Semaphore (->... '() [a a] b) (-opt (-> b)))
+                 [a a] b)))]
+[call-with-semaphore/enable-break
+ (-polydots (b a)
+   (cl->* (->... (list -Semaphore (->... '() [a a] b))
+                 [a a] b)
+          (->... (list -Semaphore (->... '() [a a] b) (-opt (-> b)))
+                 [a a] b)))]
 
 ;; Section 11.3.1 (Thread Cells)
 [thread-cell? (make-pred-ty (make-ThreadCellTop))]
diff --git a/typed-racket-test/unit-tests/typecheck-tests.rkt b/typed-racket-test/unit-tests/typecheck-tests.rkt
index 52fef588..2ad9ba71 100644
--- a/typed-racket-test/unit-tests/typecheck-tests.rkt
+++ b/typed-racket-test/unit-tests/typecheck-tests.rkt
@@ -1840,6 +1840,20 @@
         (tc-e (make-semaphore) -Semaphore)
         (tc-e (let: ((s : Semaphore (make-semaphore 3)))
                       (semaphore-post s)) -Void)
+        [tc-e (call-with-semaphore (make-semaphore)
+                                   (lambda: ([x : String]) (void))
+                                   (lambda: () "x")
+                                   "a")
+              (t:Un -String -Void)]
+        [tc-err (call-with-semaphore (make-semaphore)
+                                     (lambda: ([x : String]) (void)))]
+        [tc-err (call-with-semaphore (make-semaphore)
+                                     (lambda: ([x : String]) (void))
+                                     #f 'x)]
+        [tc-err (call-with-semaphore (make-semaphore)
+                                     (lambda: ([x : String]) (void))
+                                     'not-a-failure-thunk
+                                     "x")]
 
         ;Random Numbers
         (tc-e (make-pseudo-random-generator) -Pseudo-Random-Generator)