In the last few decades, Latin American (LA) governments have implemented innovative budget reforms to improve public spending and the overall impact of public policies. LA’s reforms sought four main objectives: enhance efficiency and effectiveness of spending; incorporate citizen participation in the budget process; increase transparency and control over public spending; and use the budget as a tool to advance rights and equality. An important part of the LA story is that, alongside these government reforms, strong civil society organizations (CSOs) emerged to demand greater accountability, transparency, and participation in the budget process. This guide presents an overview to LA’s budget reform experience, emphasizing contextual factors enabling the design and implementation of these reforms and on outcomes and lessons learned.