The study explores the link between product market competition (PMC) and firm value (FV) and examines the moderating role of the state ownership (SOE) variable in this relationship by using data from 555 listed firms on Vietnam's stock market from 2011 to 2019 on the Ho Chi Minh Stock Exchange (HOSE) and Ha Noi Stock Exchange (HNX). The System Generalized Method of Moments (SysGMM) is used to consider the relationship between variables. The findings from SysGMM indicate that product market competition has an effect on firm value. Firms with a high proportion of state ownership have a stronger correlation between product market competition and firm value than firms with a low proportion of state ownership. Additionally, we use fuzzy-set qualitative comparative analysis (fsQCA) to consider the causal relationship of variables in the model. The fsQCA results show that FV increased when the combination of lower product market competition, higher state ownership, higher firm, and lower debt ratio, which is a common trend to help clarify the evidence in emerging markets. The research is significant for investors, listed companies, and particularly organizations with state ownership, since it enables them to develop specific strategies for enhancing corporate value as the competitive market grows more challenging. Simultaneously, the study concentrated on examining the causal relationships between the variables while utilizing the FSQCA approach in order to contribute to the literature review in the emerging market.