I document that government debt is related to risk premia in various asset markets: (i) the debt-to-GDP ratio positively predicts excess stock returns with out-of-sample R 2 up to 30% at a five-year horizon, outperforming many popular predictors; (ii) the debt-to-GDP ratio is positively correlated with credit risk premia in both corporate bond excess returns and yield spreads; (iii) higher debt-to-GDP ratio is associated with lower real risk-free rates, (iv) higher debt-to-GDP ratio corresponds to lower average expected returns on government debt; (v) debt-to-GDP ratio positively comoves with fiscal policy uncertainty. I rationalize these empirical findings in a general equilibrium model featuring recursive preferences, endogenous growth, distortionary taxation, and time-varying fiscal uncertainty. In the model, the tax risk premium is sizable and its time variation is driven by fiscal uncertainty. Furthermore, the model generates an endogenous relationship between the debt-to-GDP ratio and fiscal uncertainty. Fiscal uncertainty increases debt valuation through lower government discount rate. This mechanism is reinforced as higher debt conversely raises uncertainty because of future fiscal consolidations.