As more countries grant political rights to their emigrants and more politicians look beyond national boundaries for support, scholars are beginning to explore the drivers and implications of voting from abroad. We use an original dataset of overseas campaigning by political parties in 108 elections in 24 countries to provide the first cross-national test of how party mobilization shapes turnout beyond national borders. Using fractional regression and inverse probability weighting with regression adjustment (IPWRA), we find that party mobilization increases extraterritorial voter turnout. Our results remain robust when controlling for emigrant profiles, institutional barriers to participation, and political context and correcting for self-selection bias.