Financing agriculture in Nigeria from the perspective of both conventional and Islamic sources of finance has been faced with multi-dimensional challenges that impede the agricultural sector threatening sustainable agricultural production for food security. With a population size of 206 million and 70.8 million hectares of arable land, Nigeria is threatened with a high rate of unemployment, poverty, malnutrition, and social inequality. This can be related to the lack of access to finance by smallholder farmers in financial institutions. If access to financial institutions in critical sectors like agriculture and energy can be enhanced, then there will be an increased development in the overall value chain of the agricultural sector. This review paper is aimed at (1) Evaluating the current studies of the cause and effect by looking at the roles played by private, public, and international financial institutions and agencies and (2) Outlining the research gap in the literature with a focus on comparative study on financing agriculture in Nigeria. This study is based on a multi-dimensional theoretical approach (structural-functional, dependency theory, modernization theory, human needs theory, conflict and critical theories). The paper adopted the systematic literature review and reviewed 27 relevant source documents. Based on the review of the literature, the following major results emerged: Lack of macroeconomic policy, lack of access to finance, and bureaucratic bottleneck. The literature review revealed the challenges of financing agriculture and the effect on society based on results that emerged from the study. In addition, it also revealed the practical, evidence, theoretical, population, implementation, and methodological gaps that can lead to further research study. This comparative review study contributed to knowledge in expanding the existing literature on cause and effect by focusing on the roles played by private, public, and international financial institutions and agencies in financing agriculture using multi-dimensional theories and methods to find what the causes are, why they occur, what groups are affected, how they cope in the absence of funds, and what measures to apply to improve agricultural finance.