Disclosed herein are integrated circuit (IC) structures, packages, and devices that include thin-film transistors (TFTs) integrated on the same substrate/die/chip as III-N transistors. One example IC structure includes an III-N transistor in a first layer over a support structure (e.g., a substrate) and a TFT in a second layer over the support structure, where the first layer is between the support structure and the second layer. Another example IC structure includes a III-N semiconductor material and a TFT, where at least a portion of a channel material of the TFT is over at least a portion of the III-N semiconductor material.