In this study, freshwater (Scenedesmus quadricauda, Sq) and marine water (Tetraselmis suecica, Ts) microalgae were used for the treatment of dairy wastewater (DWW). Sq and Ts showed the highest biomass productivity as 0.47 and 0.61 g/L, respectively. Removal efficiencies of total nitrogen (TN), phosphate (PO43-), and total organic carbon (TOC) were observed as 86.21, 89.83 and 64.47% by Sq and 44.92, 42.18 and 40.16% by Ts, respectively. After wastewater treatment, lipids were extracted from microalgal biomasses. Fatty acid methyl esters (FAMEs) analysis revealed that saturated fatty acids (SFAs) are dominant in Sq and polyunsaturated fatty acids (PUFAs) in Ts. After lipid extraction, removal of tetracycline (TC) from water by microalgal biomasses was also investigated. Maximum adsorption capacities of Sq and Ts were found to be 295.34 and 56.25 mg/g, respectively. Results of this study revealed the versatile applications of microalgae for wastewater treatment, lipid production and TC removal from water.