The aim of this study was to examine and compare the psychological factors influencing driver speeding behavior in 3 cities in Southeast Asia, focusing on developing counties, using the Theory of Planned Behaviour (TPB). Data was collected from 570 respondents in the urban areas of Khon Kaen in Thailand, Vientiane in Laos and Phnom Penh in Cambodia. The psychological factors of TPB include attitude (AT), subjective norm (SN) and perceived behavioral control (PBC). These factors were employed to explain speeding intentions in urban road environments. The Structural Equation Models (SEM) was used to examine and explain speeding intentions. The results indicated that the TPB could explain the variance by intentions of drivers in Khon Kaen, Vientiane and Phnom Penh at 33%, 46%, and 84%, respectively. The most significant of the psychological factors for Khon Kaen drivers was determined by AT, while the speeding intentions of Vientiane drivers and Phnom Penh drivers were determined by PBC. From this data, the authorities of each city should create and implement safety policies that can improve these psychological factors, which could have a positive effect on drivers’speeding intentions in urban road environments. The outcome of this study could be useful for understanding the speeding attitudes of drivers in three different countries and would be beneficial for the development and introduction of preventative safety measures in these countries as well.