The aim of this study was to determine the composition, biodiversity, and relative abundance of epiphytic algal species on three submerged aquatic plant species (the macrophytes Ceratophyllum demersum, Myriophyllum spicatum, and Potamogeton crispus) in Lake Gala in Lake Gala National Park, Turkey, and the associations of the observed relationships with environmental variables. The aquatic plants were collected at monthly intervals between March 2014 and November 2014, and epiphytic algae on the plants were identified. In total, 98, 74, and 66 taxa of epiphytic algae were identified on C. demersum, M. spicatum, and P. crispus, respectively. The species composition of the epiphytic algae on the three macrophyte species showed a statistically significant difference (F = 7.07, p<0.05). There was also a statistically significant difference in epiphytic algae species diversity, depending on the sampled month (F = 3.59, p<0.05). The mean species richness and species diversity on C. demersum was 33 and 1.546, respectively. On M. spicatum, the mean species richness and species diversity was 23 and 1.407, respectively. On P. crispus, the mean species richness was 19, and the species diversity was 1.256. The following species were the dominant epiphytic taxa in Gala Lake: Cocconeis placentula, Anabaena constricta, Gomphonema acuminatum, Oscillatoria limosa, Cymbella cistula, and Epithemia sorex. Although the species composition of the epiphytic algae was different, the diversity values were similar on all the macrophyte species.