Agricultural extension services play a pivotal role in global efforts to achieve food security, acting as a critical link between research, farmers, and policymakers. This comprehensive review examines the multifaceted contributions of agricultural extension to food security goals, drawing on theoretical frameworks, empirical evidence, and case studies from diverse global contexts. This paper explores how extension services address the four dimensions of food security: availability, access, utilization, and stability. It analyses the evolution of extension models, from traditional top-down approaches to participatory and market-led systems, assessing their relative effectiveness in enhancing agricultural productivity and food security. This review paper highlights innovative practices, including the integration of information and communication technologies (ICT), community-based approaches, and public-private partnerships, which have shown promise in overcoming persistent challenges. The case studies from both developed and developing countries provide insights into successful strategies and their impacts on crop yields, farmer incomes, and nutritional outcomes. This paper also addresses critical challenges facing extension services, including financial constraints, technological barriers, and socio-cultural issues, proposing potential solutions and policy recommendations. By synthesizing current knowledge and identifying future research directions, this review underscores the indispensable role of agricultural extension in achieving global food security goals and emphasizes the need for continued innovation and adaptation in extension practices to meet evolving challenges in the agricultural sector.