Berenice II Euergetis (267 or 266 BC – 221 BC; Greek: Βερενίκη Ευεργέτις, Berenikē Euergetis, "Berenice the Benefactress") was queen regnant of Cyrenaica from 258 BC to 246 BC and co-regent queen of Ptolemaic Egypt from 246 BC to 222 BC as the wife of Ptolemy III.

She married Demetrius, thus giving him the throne of Cyrenaica, on the death of her father Magas in 250/249 BC. After a short power struggle with her mother, Berenice married her half-cousin Ptolemy III, the third ruler of the Ptolemaic kingdom. This marriage led to the re-incorporation of Cyrenaica into the Ptolemaic empire. As queen of Egypt, Berenice participated actively in government, was incorporated into the Ptolemaic state cult alongside her husband and worshipped as a goddess in her own right. She is best known for sacrificing her hair as a votive offering, which led to the constellation Coma Berenices being named after her. Berenice was murdered by the regent Sosibius shortly after the accession of her son Ptolemy IV Philopator in 221 BC.