This document summarizes a study that examines the relationship between corruption and firm investment in Vietnam using survey data from Vietnamese small and medium enterprises. The study tests two hypotheses: that corruption hinders firm investment by increasing costs and promoting rent-seeking behaviors, or that corruption boosts investment by helping firms overcome bureaucratic obstacles. The study employs both a simple logistic regression model and a bivariate probit model with a corruption instrument variable to address potential endogeneity between corruption and investment. The results provide evidence that corruption hinders firm investment in Vietnam, which may partially explain the negative effect of corruption on firm performance found in previous research.