Yes, Muslims believe in Allah as the all-powerful, eternal Creator who is separate from creation, has no partners, no gender, and is the absolute sole entity worthy of human worship.
He is transcendent and not a part of his creation. He is all-powerful, absolutely Just and He is First, Last, and Everlasting; He was when nothing was, and will be when nothing else remains. Also, There is no other entity in the entire universe worthy of worship besides Him.
This belief in God is how one becomes a Muslim and is similar to the first commandment of Christianity and Judaism: You shall have no other gods before Me.
Say He is Allah,the One,
Allah the Eternal,Absolute;
He does not beget,not nor is He begotten,
And there is none like Him. [Quran 1:1-4]