A total of 188 tef genotypes including 144 pure lines selected from germplasm collection, 35 released varieties, eight breeding lines and their parents were evaluated in three replications at two locations in Ethiopia. The objectives were to assess the magnitude and pattern of phenotypic diversity in tef genotypes obtained from various sources in Ethiopia. Combined analysis of variance revealed highly significant (P < 0.01) differences among genotypes, locations and genotype by environment interaction for all studied traits. Thus, wide ranges of variations were observed for days to heading (40.3 to 60.8 days) and maturity (101 to 122.5 days), plant height (60.7 to 107.1 cm), panicle length (19.5 to 39.5 cm), number of fertile tillers per plant (2.1 to 5.5) and spikelet per panicle (156.7 to 441.7), 1000 kernel weights (20.7 to 33.0 mg), grain yield (3.7 to 7.3 t/ha) and lodging index (44.7 to 79.3%). Cluster analysis revealed six distinct clusters of 188 individual tef genotypes while the 14 populations were grouped into four distinct clusters. In general, existence of sufficient level of genetic variation was revealed for future use in tef improvement.