There is an urgent need for novel therapeutic approaches to treat Alzheimer's disease (AD) with the ability to both alleviate the clinical symptoms and halt the progression of the disease. AD is characterized by the accumulation of amyloid-beta (A beta) peptides which are generated through the sequential proteolytic cleavage of the amyloid precursor protein (APP). Previous studies reported that Mint2, a neuronal adaptor protein binding both APP and the gamma-secretase complex, affects APP processing and formation of pathogenic A beta. However, there have been contradicting results concerning whether Mint2 has a facilitative or suppressive effect on A beta generation. Herein, we deciphered the APP-Mint2 protein-protein interaction (PPI) via extensive probing of both backbone H-bond and side-chain interactions. We also developed a proteolytically stable, high-affinity peptide targeting the APP-Mint2 interaction. We found that both an APP binding-deficient Mint2 variant and a cell-permeable PPI inhibitor significantly reduced A beta(42) levels in a neuronal in vitro model of AD. Together, these findings demonstrate a facilitative role of Mint2 in A beta formation, and the combination of genetic and pharmacological approaches suggests that targeting Mint2 is a promising therapeutic strategy to reduce pathogenic A beta levels.