Bank profitability in Indonesia and Thailand fluctuated differently during 2015–2024, especially amid the pandemic and recovery, while prior empirical findings remain inconsistent. This study compares the effects of liquidity and leverage on bank profitability, controlling for firm size. Annual data from conventional banks in Indonesia and Thailand were analyzed using multiple linear regression. The results indicated that profitability in Indonesia is driven by leverage and firm size, whereas in Thailand it is affected by liquidity, leverage, and firm size. The study’s novelty lies in its 2015-2024 Indonesia–Thailand comparison. The development of previous study to the object of conventional bank with firm size control. This study contributes to enriching the ASEAN banking literature and provides strategic implications for management and regulators.