This paper presents the impacts of a participatory agroecological development project on food security and wealth levels. The Malawi Farmer to Farmer Agroecology project (MAFFA) encourages farmer experimentation, community involvement and farmer-to-farmer teaching on agroecology, nutrition and gender equity. Recent international assessments of agriculture have highlighted the urgent need for changes in farming practices in Sub-Saharan Africa, due to land degradation, high levels of food insecurity and anticipated climate change impacts. Agroecological approaches have shown great potential to address these multiple needs. Using a longitudinal panel survey data and propensity score matching to account for selection bias in project participation, we analyzed the impact of the project on household income and food security in Malawi in 2012 (Wave 1 = 1200 households) and in 2014 (Wave 2 = 1000 households). We used the Household Food Insecurity Access Scale (HFIAS) for impact evaluation. Estimates of average treatment-effects using difference in difference methods showed that participating in MAFFA has led to a significant increase in household wealth (β = 3.54, p = 0.01) and a large reduction in food insecurity (β = −3.21, p = 0.01) compared to non-participants, after 2 years, even after accounting for covariates and selection bias. These results indicate that agroecological methods combined with farmer led knowledge exchanges can be welfare enhancing, both in terms of food security and in terms of income for family farm households. Agroecological approaches should be promoted through upscaling of farmer-to-farmer knowledge exchanges, community involvement and attention to nutrition and social equity to enhance farmer learning and household welfare benefits.