Landfill studies included in the review indicate that TD estimates of CH4 emissions are generally much larger than those self-reported to government GHGRPs. In the U.S., low GHGRP self-reported rates for landfills relative to TD estimates can mainly be tied to the CEA calculation method preferred by operators for reporting, which is systematically under-estimating emissions. The studies highlighted that the main issues with this method are overestimated gas capture system efficiencies and soil oxidation rates. Methods to calculate CH4 emissions from landfills have value owing to the cost of snapshot observations of emissions with aircraft, satellites, or other measurement methods, but calculation methods are also missing emissions from fugitive point-sources within landfills at present. Thus, closing the gap between TD estimates and GHGRP self-reported CH4 rates for landfills broadly will require advances in CH4 emissions modeling approaches to address current shortcomings and the need to integrate empirical measurement data. We note that models to estimate CH4 emissions from landfills have improved considerably (e.g., CALMIM) and should be used more widely for reporting. These models should be adapted to incorporate new parameters and measurement data based on research findings and insights, like the fugitive emissions highlighted in several studies or measurement-based estimates of gas capture system efficiencies. Overall, a more integrative approach to landfill CH4 measurements and emissions modeling is recommended.