This paper attempts to attract an additional share of inbound tourists for Cambodia from the total inbound tourists in the Association of Southeast Asian Nations (ASEAN). We measure the impact of six subcomponents of institutional quality on the relative share of inbound tourists (64 countries of origin) in Cambodia to total inbound tourists in ASEAN. We consider the two-step system Generalized Method of Moments (GMM) estimation to analyze panel dataset covering 11 years (2007–2017). The estimation result shows that better rule of law, control of corruption, regulatory quality, political stability, government effectiveness, and voice and accountability increases the relative share of inbound tourists for Cambodia. The business environment, internet access, and doctors show a positive and significant effect on the relative share of inbound tourists (64 countries of origin) in Cambodia. Higher tourism price discourages tourists who visit ASEAN from visiting Cambodia. Higher transportation cost does not discourage inbound tourists who visit ASEAN from visiting Cambodia. The substitution price (Lao PDR, Thailand, and Vietnam) shows an expected sign and significant influence on the relative share of inbound tourists (64 countries of origins) in Cambodia to total inbound tourists in ASEAN. The results are robust in using another measurement of tourism development. Therefore, the government should consider ways to improve the six subcomponents of institutional quality to significantly increase the relative share of inbound tourists forto Cambodia from ASEAN.