Optimizing error correcting code (ECC) in three-dimensional (3D) stacked memory including selecting, as an ECC memory chip, a memory chip of a plurality of memory chips in a 3D stacked memory structure, wherein the 3D stacked memory structure comprises the plurality of memory chips stacked vertically and coupled together using through-silicon vias; determining that an error has been detected in one of the plurality of memory chips in the 3D stacked memory structure; selecting, based on the detected error, an order of an ECC decoder of the ECC stored in the ECC memory chip; and correcting the detected error in the 3D stacked memory structure using the ECC stored in the ECC memory chip.