In this paper, we study the influence of political and local competition on public investment expenditures. Using panel data for 304 Polish cities over the 2002–2014 period, we estimate the determinants of public infrastructure investment. The estimations show that both political competition and fiscal decentralization matter for public investment spending. A significant negative correlation was found between investment per capita (the proportion of investment in total expenditure) and the level of political competition measured by the Herfindahl-Hirschman Index (HHI). A decrease in the intensity of competition results in greater public investment per capita, while fiscal decentralization increases the share of public funds allocated for investment.