This paper investigates the intention to use private autonomous vehicles (PAVs) in developed (i.e., the United States, Belgium, the United Kingdom, Italy, Portugal, and Hungary) and developing countries (i.e., Egypt, Iraq, Jordan, Lebanon, and Saudi Arabia). Self-efficacy, the attitude toward using PAV technology, and the trust in PAV constructs are integrated into an extended Unified Theory of Acceptance and Use of Technology (UTAUT2) model to increase the understanding of users' perceptions of PAVs in developed and developing countries. The results of partial least squares structural equation modeling show the attitude toward using PAV technology to be the strongest predictor of the intention to use PAVs in developed and developing countries. Performance expectancy and trust in PAV are the strongest predictors of attitude toward using PAV technology in developed and developing countries, respectively. Effort-related constructs (i.e., effort expectancy and self-efficacy) do not directly affect the behavioral intention of the respondents from the developed countries while significantly affecting the behavioral intention of the respondents from the developing countries. The results of the mediation analysis show that the relationship between effort expectancy and behavioral intention is fully mediated by the attitude toward using PAV technology and performance expectancy for the respondents of the developed countries. Furthermore, the results of the multi-group moderation analysis show the relationship between performance expectancy and behavioral intention as well as social influence and the trust in PAV is not moderated by any of the moderators (i.e., age, gender, educational level, employment status, income level, car ownership status, and driving license status), neither for the developed countries nor for the developing countries.