This study examines the relationship between Thai anaphoric expressions and their antecedents’ Accessibility, analyzing 3,453 expressions from Thai-Zlatev Corpus (Zlatev and Yangklang 2001), Aakanee Website (Aakanee, “Thai Recordings”) and Thai Folktale Database (Princess Maha Chakri Sirindhorn Anthropology Centre, “Folktales”). Grounded in Ariel’s Accessibility Theory (1988, 1990), which asserts that referring expressions are universally arranged on an Accessibility scale but marking systems vary by language, we propose an Accessibility Marking Scale for Thai anaphoric expressions, informed by the factors of Distance, Competition, Saliency and Unity. Some anaphoric expressions showed no significant differences in mean Accessibility, leading them to share ranks. Our newly identified anaphoric expressions align on the scale with those of similar discourse function and pattern. The study also reveals that factors like Saliency and Unity account for the distinctions between the Thai Accessibility Marking Scale and the English Accessibility Marking Scale as proposed by Ariel.