Semiconductor nanowire devices having (111)-plane channel sidewalls and methods of fabricating semiconductor nanowire devices having (111)-plane channel sidewalls are described. For example, an integrated circuit structure includes a first semiconductor device including a plurality of vertically stacked nanowires disposed above a substrate, each of the nanowires comprising a discrete channel region having lateral sidewalls along a carrier transport direction. The integrated circuit structure also includes a second semiconductor device including a semiconductor fin disposed above the substrate, the semiconductor fin having a channel region with a top and side surfaces, the channel region having lateral sidewalls along a carrier transport direction.