Quinoa is recently introduced to Pakistan as a salt-tolerant crop of high nutritional value. Open field trials were conducted to evaluate its performance on normal and salinity/sodicity-degraded lands at two locations of different salinity/sodicity levels, S₁ (UAF Farm, Normal Soil), S₂ (Paroka Farm UAF, saline sodic), S₃ (SSRI Farm, normal) and S₄ (SSRI Farm, saline sodic) during 2013–2014. Two genotypes (Q-2 and Q-7) were grown in lines and were allowed to grow till maturity under RCBD split-plot arrangement. Maximum seed yield (3,062 kg/ha) was achieved by Q-7 at normal field (S₁) soil which was statistically similar with yield of same genotype obtained from salt-affected field S₂ (2,870 kg/ha). Furthermore, low yield was seen from both genotypes from both S₃ and S₄ as compared to S₁ and S₂. Q-7 was best under all four conditions. Minimum yield was recorded from Q-2 (1,587 kg/ha) at S₄. Q-7 had higher SOD, proline, phenolic and K⁺ contents, and lower Na⁺ content in leaves as compared to Q-2. High levels of antioxidants and K⁺/Na⁺ of Q-7 helped to withstand salt stress and might be the cause of higher yields under both normal and salt-affected soils. Seed quality (mineral and protein) did not decrease considerably under salt-affected soils even improved seed K⁺, Mg²⁺ and Mn²⁺.