The present invention relates generally to thienopyrimidine and thienopyridine class compounds and methods of use thereof. In particular embodiments, the present invention provides compositions comprising thienopyrimidine and thienopyridine class compounds and methods of use to inhibit the interaction of menin with MLL1, MLL2 and MLL-fusion oncoproteins (e.g., for the treatment of leukemia, solid cancers and other diseases dependent on activity of MLL1, MLL2, MLL fusion proteins, and/or menin).