diff --git a/dlls/comctl32/monthcal.c b/dlls/comctl32/monthcal.c
index 384efe78432..ed059ff2981 100644
--- a/dlls/comctl32/monthcal.c
+++ b/dlls/comctl32/monthcal.c
@@ -1087,9 +1087,10 @@ MONTHCAL_SetMaxSelCount(MONTHCAL_INFO *infoPtr, INT max)
 {
   TRACE("%d\n", max);
 
-  if(infoPtr->dwStyle & MCS_MULTISELECT)  {
-    infoPtr->maxSelCount = max;
-  }
+  if(!(infoPtr->dwStyle & MCS_MULTISELECT)) return FALSE;
+  if(max <= 0) return FALSE;
+
+  infoPtr->maxSelCount = max;
 
   return TRUE;
 }
diff --git a/dlls/comctl32/tests/monthcal.c b/dlls/comctl32/tests/monthcal.c
index cd9d15eb863..e0479cd075a 100644
--- a/dlls/comctl32/tests/monthcal.c
+++ b/dlls/comctl32/tests/monthcal.c
@@ -1316,6 +1316,10 @@ static void test_monthcal_maxselday(void)
     /* if no style specified default to 1 */
     res = SendMessage(hwnd, MCM_GETMAXSELCOUNT, 0, 0);
     expect(1, res);
+    res = SendMessage(hwnd, MCM_SETMAXSELCOUNT, 5, 0);
+    expect(0, res);
+    res = SendMessage(hwnd, MCM_GETMAXSELCOUNT, 0, 0);
+    expect(1, res);
 
     /* try to set style */
     style = GetWindowLong(hwnd, GWL_STYLE);
@@ -1351,13 +1355,20 @@ static void test_monthcal_maxselday(void)
     res = SendMessage(hwnd, MCM_GETMAXSELCOUNT, 0, 0);
     expect(15, res);
 
+    /* test invalid value */
     res = SendMessage(hwnd, MCM_SETMAXSELCOUNT, -1, 0);
-    todo_wine {expect(0, res);}
+    expect(0, res);
     res = SendMessage(hwnd, MCM_GETMAXSELCOUNT, 0, 0);
-    todo_wine {expect(15, res);}
+    expect(15, res);
 
     ok_sequence(sequences, MONTHCAL_SEQ_INDEX, monthcal_max_sel_day_seq, "monthcal MaxSelDay", FALSE);
 
+    /* zero value is invalid too */
+    res = SendMessage(hwnd, MCM_SETMAXSELCOUNT, 0, 0);
+    expect(0, res);
+    res = SendMessage(hwnd, MCM_GETMAXSELCOUNT, 0, 0);
+    expect(15, res);
+
     DestroyWindow(hwnd);
 }