Many tax systems differentiate between households based on their composition, for example through joint taxation of married couples or income thresholds that depend on the number of children. Yet, the effective tax functions commonly used in public finance and macroeconomics to describe tax systems typically abstract from this feature. As a result, researchers often need to specify and estimate separate tax functions for each possible household type. This project addresses this limitation by generalizing the widely used tax function from Gouveia and Strauss (1994) to explicitly incorporate family structure within a single, unified parametric specification. Using US Current Population Survey data since the 1960s, the study provides empirical estimates for use in applied work and documents the evolution of income taxation across household types in the United States.