Question: Who is the deity or god That muslims worship? 

Answer: The deity Muslims worship is referred to in Islam as "Allah", which is really the Arabic word for God (descended from the Aramaic word for god, which translates as "Elah").  \n\nIn reality, Muslims worship the Hebrew god אֶהְיֶה ( and you should read that name from right to left instead of left to right as you would if the name was written in English, since Hebrew is written in the opposite direction).\n\nThe name of the God, should you need a way to pronounce it in English, can roughly be translated as Yahweh, or more loosely as Jehovah.  \n\nIt is the same god worshiped as the god of Creation and the Universe in Judaism, and in Christianity as well, since both Islam and Christianity descend from Judaism and are seen as different, updated ways the one true god of the Hebrews has instructed mankind to worship Him (the practical upshot of which is that while all three religions worship the same god, none of the three see the other two as really being valid since, in all three cases, each religion views the other two as being in error about god's will... the Jews because they do not believe either Jesus or Mohammad and their teachings are valid... the Christians because they believe the teachings of Jesus and his interpretations leading to Christianity render the other two invalid, and the Muslims because they believe the teachings of Mohammad and his interpretations leading to Islam do the same).
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