Tecoma stan is a tropical plant widely used in Asian folk medicine. However, little is known about the phytochemical data of the plant growing in Vietnam. In the present study, the phytochemical analysis of the flowers of T. stans collected in Vietnam was conducted using multiple chromatographic methods. The chemical structures of isolated compounds were identified by comprehensive spectroscopic methods. Three megastigmanes dehydrovomifoliol (1), vomifoliol (2), and dendranthemoside B (3) were isolated from the flowers of Tecoma stans (Bignoniaceae) by different chromatographic techniques. Their chemical structures were elucidated through the spectroscopic methods along with the comparison of their NMR data with the published data. To the best of our knowledge, compounds 1-3 were known to present in this species for the first time