Abstarct: In order to investigate the planting date effect on the phenological stages, yield and quality of quinoa (Chenopodium quinoa willd) seeds, a research was conducted in Shavilasht region of Sari in Mazandaran province in the cropping year of 2023. The experiment was done as a split plot baxsed on a randomized complete block design with four replications. The experimental treatments included five planting dates (6 March, 26 March, 15 April, 5 May and 25 May) and three cultivars (Rahmat, Sadough and Titikaka). In this research, the plants sown on 25 May did not reach the stage of seed production due to exposure to heat and drought, and sometimes they were stressed and wilted in the very early stages of growth. With this reason, the data related to this date was removed and other cultivation dates were examined. The results showed that the highest amount of photosynthetic pigments including chlorophyll a, chlorophyll b, total chlorophyll and carotenoid was observed on the third planting date (15 April). Early planting (6 March) caused an increase in plant height, total dry weight, relative leaf water content, leaf area index and thousand seed weight. The latest planting date (5 May) had the lowest plant height, total dry weight, leaf area index, phenological traits and 1000 seed weight in all three cultivars. The amount of proline increased with delay in planting in all three cultivars. Among the examined cultivars, the highest plant height, panicle length, total dry weight and leaf area index were related to Titikaka variety. Among the three cultivars, Sadough cultivar had the highest thousand seed weight and seed yield. The highest percentage of seed protein was also obtained in Sadough variety and planting time on 6 March (20.08%). The seed yield in the plants that were cultivated on 26 March was at the highest level, which was 1038.53 and 1193.5 kg/ha in the two cultivars of Titikaka and Sadough, respectively. Finally, within the scope of the research, the Sadough variety cultivation on 26 March is recommendable for Shavilasht region in Sari.