Koroinen (Finnish; Korois in Swedish) is a ward (suuralue, storområde) of Turku, Finland, also known as Ward 5.
The ward is located to the northeast of the city centre and named after Koroinen, a district in the centre of the ward.
14.76% of the ward's population are under 15 years old, while 6.25% are over 65.
It is one of the most multicultural of the city's wards, and this is reflected in the linguistic makeup, which is 83.01% Finnish, 5.42% Swedish, and 11.57% other.
The ward consists of five districts.