Sakai-ku (堺区?) is a ward of the city of Sakai in Osaka Prefecture, Japan. The ward has an area of 23.69 km² and a population of 147,413. The population density is 6,223 per square kilometer.
The wards of Sakai were established when Sakai became a city designated by government ordinance on April 1, 2006.
The city has its municipal headquarters in Sakai-ku and Sakai City Museum is located in the area.
• Central stations: Sakai-Higashi Station, Sakai Station, Sakai-shi Station
Coordinates: 34°34′24″N 135°28′59″E / 34.57333°N 135.48306°E