Background: Landfill activities have environmental and economic values to a community. While the former deals with the control of landfill gas (LFG) emission into the atmosphere, the latter deals with the conversion of LFG to clean energy and subsequently, wealth creation. To fully harness these benefits, LFG plants must be well sited in a community, and this can be achieved when proper techno-economic analysis has been carried out. This will not only justify the LFG plants investment cost, but it will also guarantee their sustainability. Methods: This study presented a framework that ranks and selects LFG project for a community. First, numerical expressions were used to evaluate the techno-economic and environmental requirements of the project sites, then, the importance of these requirements was determined using criteria Importance Through Inter-criteria Correlation (CRITIC) method. The sites were ranked using grey relational analysis (GRA) and Weighted Aggregated Sum-Product Assessment (WASPAS) method. An illustrative example of the proposed framework was presented using real-world dataset from different communities in Nigeria. Finally, four LFG project sites were ranked using four environmental criteria, five technical criteria, and eight economic criteria. Results: The results of WASPAS were verified by comparing them with the results of Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) and axiomatic design (AD) methods. It was observed that the results of both methods were the same for the different LFG sites. Conclusion: According to the results, it is obvious that this study will be useful to policy-makers and investors in LFG business, while the former could seek for plants’ sustainability, the latter interest will be on the payback period of their investment.