St. Mary’s Lwak Girls' School is a Girls only boarding school located in West Asembo location, Rarieda Sub County, Siaya County in Kenya. The school was started in 1965 by The visionary Franciscan 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, the sixth stream in 2011 and currently it’s registered as nine streams with a population of 1,831 students served by a teaching staff of 78 and 75 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 facilities which are fully overstretched. It has 29 classrooms, 6 laboratories, 20 dormitories, 3 dining halls, 2 libraries and references section, CT library an Assembly hall, staffroom, administration block, French room, computer room, Home science rooms, departmental offices, 89 flash toilets, 20 pit latrines.