Here, we investigated physiological responses, yield components, starch properties, and starch biosynthesis genes in five Thai rice ( L.) cultivars (SPR1, Hawm Daeng, RD43, RD69, and PTT1) with distinct starch characteristics under salt stress. Salt stress decreased flag leaf greenness (SPAD), normalized difference vegetation index (NDVI) levels, and carotenoid reflectance index 1 (CRI1) levels in all cultivars, resulting in reduced net photosynthesis, transpiration rates, and yield components across all cultivars, with Hawm Daeng and PTT1 being most susceptible. In contrast, RD69 and SPR1 were more tolerant, exhibiting recovered chlorophyll fluorescence levels and total performance index values after 3 days. Salt stress reduced apparent amylose content (AAC) and increased rapidly available glucose (RAG) levels in all cultivars. () expression declined the most in PTT1 and Hawm Daeng. SPAD, NDVI, CRI1, and photosynthetic parameters were correlated with expression at the milky and dough stages of grain development. expression levels showed little to no correlation with slowly available glucose but correlated with resistant starch levels at the booting stage of grain development. Salt stress affected yield components and rice starch quality, with variations depending on salt susceptibility, which in turn affected expression levels during the milky and dough stages of grain development.