In developing countries, lack of critical infrastructure, such as roads, railways, ports, and power, is one of the major barriers to doing business and rural development. This research seeks to examine the complementarity between public infrastructure investment and farm investment, and their impacts on farmers’ productivity. Using the primarily collected data, the quantitative analysis reveals that households with better access to public infrastructure tend to invest with higher value on farm equipment. Canals are the most significant determinant on private farm investment for Vietnamese shrimp farmers, when compared to other types of public infrastructure. Households in remote area with inadequate access to infrastructure are found to have lower farm investment and hence lower productivity. However, when access to infrastructure reaches a peak level, farmers are likely to reduce their agricultural investment and shrift to non-farming sectors.