This paper estimates immigration’s effects on native welfare in a general-equilibrium search-and-matching model with two skill groups, capital accumulation, knowledge spillovers, and progressive taxation. Immigration affects job creation, productivity, and public finances, interacting with tax systems that differ in both size and progressivity. We calibrate the model to 17 OECD economies using 2015–2019 data on wages, unemployment, immigrant–native gaps, skill composition, and fiscal aggregates. We then simulate a one–percentage-point increase in immigrant stocks under alternative skill compositions. Skill-neutral inflows generate near-zero average welfare effects, while inflows biased toward high-skilled workers raise native welfare in almost all countries. In contrast, inflows biased toward low-skilled workers tend to reduce native welfare in many, though not all, cases, with outcomes varying across countries. Fiscal structure plays a central role in shaping these results: tax progressivity reallocates the fiscal incidence of immigration across skill groups, while government size mainly scales aggregate effects. As a result, identical immigration shocks can generate different welfare outcomes across countries, reflecting differences in wage gaps, unemployment conditions, and fiscal wedges rather than skill composition alone.