Agathokleia (Greek: Ἀγαθόκλεια) was a mistress of King Ptolemaios IV Philopator of Egypt. She and her brother Agathokles (the younger) were children of Agathokles (the elder) and Oinanthe.
Her mother Oinanthe introduced Agathokleia and Agathokles (the younger) to Ptolemaios IV, and Agathokleia became Ptolemaios IV's mistress, while Agathokles (the younger) became a minister. Agathokleia and her brother wielded much influence over Ptolemaios IV.
When Ptolemaios IV died, Agathokleia, Agathokles (the younger), and another influential minister named Sosibios had Philammon assassinate queen dowager Arsinoe III Philopator so that Agathokles (the younger) and Sosibios could serve as regents for Arsinoe's young son Ptolemais V Epiphanes. Agathokles later had Sosibios killed as well.
The people learned of the truth behind Arsinoe's death. Agathokles (the younger) was killed, and a mob killed and dismembered Agathokleia, their sisters, and their mother Oinanthe. A mob also killed Philammon.
Tlepolemos then became Ptolemaios V's regent.