The article examines changes in the level of the Caspian Sea as a result of predominantly endogenous factors, including tectonic subsidence and uplift of the seabed, as well as quasi-periodic variations in the stress state of lithospheric plates, manifested through regimes of compression, extension, and stabilization. Exogenous influences are also analyzed, such as river inflow volume, water balance, evaporation rates, wind effects, and other climatic parameters. The potential connection between long-term sea level fluctuations and variations in solar activity is discussed. As an empirical basis, the study uses data from statistical analyses of historical and archaeological sources, along with the results of instrumental observations of the Caspian Sea level.