This study aims to determine the types of Phytoplankton in Ranau Lake regency OKU Selatan. This research was conducted at Ranau Lake and the FKIP UNSRI Biology Education Laboratory in March-May 2023. This study used a descriptive method to describe the types of phytoplankton by taking samples using a purposive sampling technique and direct observation with 4 points of phytoplankton sampling sta…