Under the paradigm of factor investing, we create a global factor allocation strategy using country indexes and portfolio construction methodologies that are robust to estimation error. Implementable through exchange-traded funds or index futures, a portfolio based on country indexes with favorable factor exposures significantly outperforms, both economically and statistically, the world market capitalization portfolio. The outperformance remains significant after taking into account transaction costs, alternative portfolio construction methodologies, and tracking error constraints. From a practical investment perspective, country-based factor portfolios offer a viable alternative implementation of factor investing in a world of illiquidity, transaction costs, and capacity constraints.