St. Mary’s Lwak Girls' School is a Girls only boarding school located in West Asembo location, Rarieda Sub County, Siaya County . The school was started in 1965 by The visionary Fransiscan Sisters of St.Anna-Oudenbosch. It began as a harambee school with a population of 30 students.It became an A level school in the 70’s offering Arts and Sciences.Following the introduction of the 8.4.4 system, the school started a third stream in 1987 and a fourth stream in 1999. In 2008,it started the fifth stream and the sixth stream in 2011. The school population currently stands at 1,543 students served by a teaching staff of 65 and 61 support staff. The school has enjoyed relative stability because of the competence exhibited by the leadership, the hard work of the staff, the generosity of parents and donors and the focused students. The school has the following facililities which ae fully utilized. It has 24 classrooms, 6 laboratories, 20 dormitories, 3 dinning halls, 2 libraries and references section,ICT library an Assembly hall, staffroom, administration block, Frenchroom, computer room, Homescience rooms, departmental offices, 89 flash toilets, 20 pit latrines.