This study aims to examine the effect of firm size, capital structure, and earnings quality on firm value, with tax planning as a moderating variable, in food and beverage companies in Southeast Asia. This research employs a quantitative approach using panel data from 50 companies across five Southeast Asian countries during the period 2022–2024. The data were analyzed using moderated regression analysis with a random effects model, processed with Stata software. The results indicate that firm size and earnings quality significantly affect firm value, while capital structure does not have a significant effect. Furthermore, tax planning is found to strengthen the relationship between firm size and firm value, but it does not moderate the effect of capital structure and tends to weaken the relationship between earnings quality and firm value. The coefficient of determination shows that the variables in the model explain more than half of the variation in firm value. These findings suggest that firm value is influenced not only by internal company factors but also by the firm’s tax planning strategy. This study is expected to provide insights for company management in formulating financial strategies and for investors in making investment decisions.