Therefore, this study aims to fill that gap by investigating narrative TBL reporting in the annual reports of the top 50 largest Thai listed companies, testing whether there is any relationship between the extent of TBL reporting and a variety of factors used in previous studies conducted in more developed countries. The study also compares its findings with findings reported in previous studies relating to TBL reporting in developed countries. There are three research questions in this study 1) Is there TBL reporting in any of the annual reports of listed companies in the SET; 2) What are the factors influencing TBL reporting;and 3) What differences are there in the extent of TBL reporting found in the present study conducted in a developing country and that found in previous studies conducted in developed countries. The remainder of this paper is organized as follows. Section 2 reviews the theoretical perspective. Section 3 discusses the background of TBL reporting in Thailand. Sections 4 and 5 review relevant literature and identify the factors potentially influencing TBL reporting. Section 6 details the research design and methodology including the methods of data analysis employed. The study findings are presented in section 7, and finally, the conclusions and limitations of the study are set out in section 8.