Three genotypes of spring onion (Allium fistulosum) were evaluated across a range of growth and quality criteria to ascertain their relative yield, quality performance and adaptability in Sylhet region. Results revealed that the tallest plant was BARI Pata Piyaz-1 with 56.78 cm, followed by JAF-2 (46.1 cm) and minimum value was recorded for JAF-1 (42.1 cm). The number of leaves per plant was the highest in JAF-2 (16.32) followed by BARI pata piaz-1 (11.56) and JAF-1 (7.32). The BARI pata piaz-1 had the highest pseudo stem diameter (1.43 cm), weight (5.81 g/pseudo stem), and dry matter (DW) content (13.19%), whereas the JAF-1 had 1.09, 4.32cm, 13.12%, and the JAF-2 had 1.11, 3.88 cm, 11.06%, respectively. Notably, JAF-2 produced the highest yield with a value of 11.34 ton/ha, which was considerably greater than BARI Pata Piyaz-1 (10.71 ton/ha) and JAF-1 (7.11 ton/ha). In terms of quality metrics, BARI Pata Piyaz-1 and JAF-2 had the identical total phenolic content ranging from 3.23-3.34 mg GAE/g DW, while JAF-1 had significantly less phenolics at 2.93 mg GAE/g DW. Significant amounts of flavonoids were detected in each genotype, ranging from 3.11 to 3.19 mg QE/g DW. The Vitamin C content of BARI Pata Piyaz-1 was significantly higher than that of other two genotypes. The current findings indicated that spring onion more specifically JAF-2 has successfully adapted in the Sylhet region with remarkable yield indicating tremendous scope in popularize this spice in future.