Context: Climate change poses significant challenges to food security, especially in arid and semi-arid regions like Iran. Identifying resilient crops and effective adaptation strategies is crucial to maintaining agricultural productivity. Objective: This study aims to evaluate the viability of quinoa, a stress-tolerant and nutritionally rich crop, as a climate-resilient alternative in Iran's diverse agro-climatic zones under projected climate change scenarios. Methods: Ten CMIP6 global climate models (GCMs) were assessed for their performance in simulating historical climate data (1990-2014) across 25 sites. Seven high-skill models were selected and downscaled under SSP2-4.5 and SSP5-8.5 pathways to project future climate in Iran through 2100. The CROPGRO-quinoa model simulated yield responses with and without elevated COQ. The effect of planting date adjustment as an adaptation measure was also analyzed. Results and conclusions: The CROPGRO-quinoa accurately simulated yields (R2 = 0.95; NSE = 0.94) under existing weather in Iran. Without COQ enrichment, quinoa yields declined on average by 22.6 % (SSP2-4.5) and 19.8 % (SSP5-8.5) during 2026-2050, though reductions eased over time relative to the 1990-2014 baseline. Accounting for COQ effects alleviated yield losses, with a potential average gain of 4.7 % under SSP5-8.5 in ELSEVIER SCI