SignificanceUveal melanoma (UM) is a cancer of eye melanocytes. Although relatively rare, UM is extremely deadly, as approximately half of all patients develop liver metastases for which there are no approved therapies. Even therapies that succeed in cutaneous melanoma (CM) treatment have proven ineffectual for UM, highlighting both the distinct nature of these two melanomas and the need to understand the differences between them. Here, we show that autochthonous UM tumors are rapidly induced by activated YAP and can lack hyperactive ERK, highlighting YAP as a promising therapeutic target. We further show that MITF functions as a tumor suppressor in UM in contrast to its essential role in CM, establishing that MITF inhibition should not be entertained for UM treatment.