This study is basically and centrally focused on the review of the extant literature in exploring the challenge of the under-utilization of natural fertile land for the cultivation and farming of different crops such as cocoa, palm tree, and cassava, which remain an important sector of the economy for sustainable socio-economic development in the southern part of Nigeria. The review of the cursory literature is necessary to bridge the gap in the existing body of knowledge, especially by addressing the less attention paid to exploring the non-oil sector of the economy such as cocoa, palm tree, and cassava as well as connecting policy and agro-technology to maximize agricultural productivity for the purpose of sustainable socio-economic development. The primary objective of this study is to explore cocoa, palm tree, and cassava plantations among smallholder farmers in order to enhance sustainable socio-economic development in the country. The methodology used in this study is a systematic literature review (SLR) cum content analysis (CA) of secondary sources or relevant literature whereby six themes were generated and analyzed. A consistent approach was used in order to establish exhaustive searching strategies and single-line search strategies such as using field codes and parentheses as part of a systematic literature review. The results indicated that smallholder farmers have been actively partaking in cocoa plantation, and the government has been supportive of them in this regard in order to achieve sustainable socio-economic development. In addition, agricultural transformation contributes to economic diversification through innovative policy and capacity building among cocoa, palm tree, and cassava farmers in the country, which culminates in improving the overall welfare of the smallholder farmers in attaining sustainable socio-economic development. In conclusion, it is noteworthy to say that giving support, especially cocoa, palm tree, and cassava seedlings, to smallholder farmers can be instrumental in bridging the vacuum created by poverty and unemployment which could be regarded as mechanisms for attaining sustainable development. The importance of the study was manifested in the practical aspect of giving concrete support to the smallholder farmers, and the innovativeness of the study is reflected in the advocacy for the efficiencies and effectiveness of agricultural policy and technology integration into the sector. It is therefore suggested that interventions of individual philanthropists, government, and international communities will boost the morale and resilience of the farmers toward enhancing cocoa, palm tree, and cassava production in order to enhance sustainable socio-economic development among smallholder farmers in particular and to maximize national economy growth in general.