This study is focused on the plankton diversity of the Ganga River during the year 2016. Plankton samples were collected monthly from the Ganga River. During the present study, phytoplankton and zooplankton were identified under the microscope with the help of standard photographs of Edmondson (1959). During the study period, Chlorophyceae (50%) was followed by bacillariophycae (37%) and Cyanophyceae (13%). Zooplankton diversity was also identified during the study period. During the study rotifers (40%) were the dominant group followed by protozoa (34%), Cladocera (23%) and Copepoda (3%). It was also found that plankton diversity was higher during the winter season followed by the summer season and minimum during the monsoon season. It was also revealed that anthropogenic activities also reduce the plankton diversity.