Het Rijnlands Lyceum Oegstgeest (informally RLO) is a secondary school in the town of Oegstgeest in South Holland, founded in 1956.
Het Rijnlands Lyceum Oegstgeest is part of the Rijnlands Lyceum Foundation, which also contains other schools in the region, including the International School of The Hague and the European School of the Hague, and formerly the Rijnlands Lyceum Dubai. The school building was designed by Rudi Bleeker, and the newly built wing from 2004 was designed by .
RLO alumni include many significant Dutch political or public figures (Including Cabinet minister Jet Bussemaker and current Deputy Prime Minister of the Netherlands Kajsa Ollongren).
The Rijnlands Lyceum Oegstgeest offers two streams of Dutch secondary education: "higher general continued education" (HAVO), and "preparatory scientific education" (VWO). The school also offers bilingual education (TTO), in English and Dutch. In addition, the Rijnlands Lyceum Oegstgeest has an international department offering the International Baccalaureate Middle Years Programme (IB MYP) and International Baccalaureate Diploma Programme (IB DP).