The reign of Khan Islam III Geray of the Crimea coincided with one of the most chaotic eras in East European history which was sparkled by the Cossack rebellion of 1648 under the leadership of Bohdan Khmelnytsky against the Polish-Lithuanian Commonwealth. The subsequent anti-Polish alliance between Islam III Geray and Bohdan Khmelnytsky has been seen in scholarship as a classical example of the Crimean Khanate's policy towards its northern neighbours. According to this view, Islam III Geray supported the Zaporozhian Cossacks against the Polish crown in order to weaken both of them as well as to present his subjects with an opportunity of plunder-raids. It has also been argued that the Crimean khan betrayed Bohdan Khmelnytsky by concluding agreement with the Polish crown on several occasions without consent or even knowledge of his Cossack allies. However, this mainstream interpretation does not survive a close scrutiny of primary sources. Crimean diplomatic correspondence and other materials originating in the circle of Islam III Geray strongly suggest that the khan did not want to get involved in a prolonged war against the Commonwealth lest it undermined the possibility of restoring the Polish authority over the Zaporozhian Cossacks. From the perspective of Islam III Geray, the conflict between Bohdan Khmelnytsky and the Polish crown had to be resolved by an agreement that would guarantee the Zaporozhian Cossacks their traditional rights and privileges in return for their acceptance of the continuation of Polish suzerainty. The principal objectives of Islam III Geray in supporting Bohdan Khmelnytsky’s uprising were to punish the Polish crown for its failure to pay the tribute due to the khanate, to retaliate for the recent expeditions of the Polish troops, and also to provide his subjects with an opportunity of looting and slave raiding which would help erase the unfortunate effects of livestock epidemics, harvest failures, and a recent civil war between the khan’s troops and the Khanate’s tribal forces. This paper will substantiate the interpretation proposed with a detailed analysis of Islam III Geray’s attitude towards the Zaporozhian Cossacks and the Polish crown in the course of Bohdan Khmelnytsky’s uprising.