This paper studies cross-sectional determinants of the exposure of U.K. firms to Brexit, an event which resulted in an unprecedented rise in political uncertainty. We find that internationalization has a moderating effect on Brexit exposure which goes beyond the pure currency translation effect and is consistent with international activities acting as a diversification mechanism for domestic risks. We also provide some indicative evidence that high-growth firms are more affected by Brexit. At the industry level, we show that Financials and firms in the consumer-facing sectors have the highest exposure to Brexit-related uncertainty. Knowledge of the variation in exposure of individual firms and sectors to political uncertainty associated with major political events can assist managers, investors and policymakers in taking remedial actions to limit its impact.