Integrated circuit structures having cavity spacers, and methods of fabricating integrated circuit structures having cavity spacers, are described. For example, an integrated circuit structure includes a sub-fin structure over a stack of nanowires. A gate structure is vertically around the stack of nanowires. An internal gate spacer is between vertically adjacent ones of the nanowires and adjacent to the gate structure. A trench contact structure is laterally adjacent to a side of the gate structure. A cavity spacer is laterally between the gate structure and the trench contact structure.