Ptolemy X Alexander I (Greek: Πτολεμαῖος Ἀλέξανδρος, Ptolemaĩos Aléxandros) was King of Egypt from 110 BC to 109 BC and 107 BC till 88 BC.
He was the son of Ptolemy VIII Physcon and Cleopatra III. In 110 BC he became King with his mother as co-regent, after his mother had deposed his brother Ptolemy IX Lathyros. However, in 109 BC he was deposed by Ptolemy IX. In 107 BC he became King again, and again with his mother as co-regent. In 101 BC he had his mother killed, and ruled either alone or with his niece/wife, Berenice III.
When he died, Ptolemy IX regained the throne. When Ptolemy IX died, Ptolemy X's wife Berenice III took over the throne for six months.