The Greek Wikipedia (also Hellenic Wikipedia, Elliniki Vikipedia, Greek: Ελληνική Βικιπαίδεια) is the Greek-language edition of Wikipedia, the free online encyclopedia. It was started on December 1, 2002. It surpassed the 10,000 article mark on May 16, 2006, the 100,000 article mark on April 9, 2014, and the 200,000 article mark on November 27, 2021. As of April 20, 2023, it is the 50th largest Wikipedia, behind Minangkabau and ahead of Croatian.

Greek Wikipedia is the main free internet encyclopedia written in Greek. Its main competitor, Livepedia, started on 2004, and had more than 100,000 articles. Many articles of Livepedia were republished articles from donations of various publishing houses and the site was also a wiki. Approximately 250 articles are coming at least partially from Livepedia, thanks to the Livepedia's use of GFDL until November 1, 2008. As of 2018, Greek Wikipedia's pageviews surpassed the 250 million mark annually. The daily pageviews of Greek Wikipedia vary within the year; peaking in the winter period (late November to mid March), while the months with the least pageviews are usually June, July and August. The active users are 1,040 today (as of April 20, 2023). The highest and lowest active users' numbers are recorded in the same period.

The Greek Wikipedia's community has organized some meetups as well. Since 2011, the Wikimedia User Group Greece has aided in the organization of various promotional activities, as well as some article contests.