Various implementations described herein may be directed to using inter-tier vias (IVs) in integrated circuits (ICs). In one implementation, a three-dimensional (3D) IC may include a plurality of tiers disposed on a substrate layer, where the tiers may include a first tier having a first active device layer electrically coupled to first interconnect layers, and may also include a second tier having a second active device layer electrically coupled to a second interconnect layer, where the first interconnect layers include an uppermost layer that is least proximate to the first active device layer. The 3D IC may further include IVs to electrically couple the second interconnect layer and the uppermost layer. The uppermost layer may be electrically coupled to a power source at peripheral locations of the first tier, thereby electrically coupling the power source to the first active device layer and to the second active device layer.