Wrap-around contact structures for semiconductor nanowires and nanoribbons, and methods of fabricating wrap-around contact structures for semiconductor nanowires and nanoribbons, are described. In an example, an integrated circuit structure includes a semiconductor nanowire above a first portion of a semiconductor sub-fin. A gate structure surrounds a channel portion of the semiconductor nanowire. A source or drain region is at a first side of the gate structure, the source or drain region including an epitaxial structure on a second portion of the semiconductor sub-fin, the epitaxial structure having substantially vertical sidewalls in alignment with the second portion of the semiconductor sub-fin. A conductive contact structure is along sidewalls of the second portion of the semiconductor sub-fin and along the substantially vertical sidewalls of the epitaxial structure.