The budget of the European Union has three pillars: its expenditure, its financing and its audit. This briefing looks at the origins of the budget, its development through multiannual planning and annual budgeting. It does so amid the European Parliament’s changing powers over the budget, and the evolution of its financing and of the audit process. Since the very first European Community in 1952, there has been a tension over budgeting among the European institutions and the Member States, and a close link between reforms to expenditure and those to the financing.