In light of a reinvigorated policy orientation toward agriculture in developing countries following recent dramatic developments affecting food prices and agricultural land use, public resource allocation decision-makers ought to have access to the existing evidence from academic research on the impact of public investments related to and in support of agriculture. The objective of this review paper is to synthesize available knowledge on the impact of public investments in and for agriculture in developing countries and to draw conclusions from this body of work to help determine policy and future research directions.