The agreement runs through to the 2024-25 season, with the competition to be renamed the Stoiximan Super League with immediate effect.
Stoiximan will also benefit from a branding presence inside stadia, work with the league on a range of social initiatives and launch a series of actions to improve the fan experience at matches.
“2023 is a pivotal year for Stoiximan, marking the completion of our first decade of life and our entry into a new period of growth,” Stoiximan vice-president Panos Konstantopoulos said.
“Our scope of cooperation goes beyond a typical sponsorship cooperation and extends to the expansion of the social footprint of Greek football, which is always the basis of our cooperation.
“We want to be a positive factor for the further development of football and as such we perceive our role as sponsors and naming partner of the Greek Super League.”
Panathinaikos currently sit top of the 2022-23 Super League, four points ahead of AEK Athens in second.