Amaranths are versatile, dicotyledonous plants with the potential for high yields. It has been extensively investigated as a model C4 plant. They have great photosynthetic performance as a result of eliminating the rival photorespiration mechanism. This increases the advantages of expanding the adaptation and cultivation of amaranth in Ethiopia. The objectives of the current study were to estimate genetic diversity, heritability, and genetic advance for yield and yield-contributing traits of amaranth genotypes based on agro-morphological traits. One hundred twenty amaranth genotypes were evaluated over two years using an alpha lattice design with two replications. The analysis of variance indicated that the mean square due to year and genotype-by-year interaction varied significantly for most measured traits. The estimates of variability, heritability, and genetic advance found in this study indicate the incredible genetic diversity in amaranth genotypes and the strength of selection response for these traits in the population. The findings showed that very high to moderately high heritability, high to moderate genetic advance, and genetic variability was observed for the traits basal lateral branch length, axillary inflorescence length, leaf area, branch number, plant height at flowering, plant height at maturity, stem diameter, days to flowering, grain filling periods, leaf width, and leaf length. Furthermore, the potential for amaranth improvement through appropriate selection is revealed by the existence of significant differences between the number of superior and inferior genotypes for the majority of examined traits. This suggests that these traits are governed more by additive gene action and that selection based on these traits might be successful in achieving the desired genetic gains for improvement.