The phenotypic diversity and adaptability of 228 introduced garlic (Allium sativnm L.) germplasm accessions originated from 34 countries were evaluated in the present study. The field trial was performed at the national germplasm repository for vegetables. The coefficient of variation of 13 quantitative traits ranged from 18.94% to 56.36%. These genotypes represented visible variations on all qualitative traits except leaf shape. The diversity index of 25 traits varied from 0 to 2.03, indicating that the introduced garlic germplasm maintained high levels of genetic diversity. The clustering analysis of 228 accessions revealed three groups. The accessions within group I showed small and slender plants, short and thin leaves, and low quality bulbs. The group II was comprised of those accessions that transverse diameter of bulbs were small, and bulbs were less and the bulbs shape were high spherical. The accessions in group III mostly exhibited tall and big plants, long and wide leaves, and heavy and large bulbs. The first three principal components explained 69.94% of phenotypic variation. The bulb weight was found to be significantly and positively correlated with bulb diameter, bulb height, height of scale buds and width of scale buds. Furthermore, these accessions were variable on adaptability by comparing the measurements of bulb-related traits before planting with that of after harvest. Thus, these results will provide benefits for breeders and researchers in order to take use of the germplasm accessions in breeding programs.