Some embodiments include a transistor having a gate, with the gate being over a semiconductor base. The gate has sidewalls. A channel region is under the gate. Spacers are along the sidewalk. The spacers each include a spacer structure and a void between the spacer structure and the gate. The spacer structures each include a vertical segment extending upwardly from a horizontal segment. The vertical segments join to the horizontal segments at corners. Source/drain regions are adjacent the channel region. The voids may be along the entirety of the vertical segments of the spacer structures, and may extend around the corners and to under the horizontal segments of the spacer structures. Additionally, or alternatively, bottoms of the voids may be adjacent fill material which includes silicon, nitrogen, boron and oxygen. Some embodiments include methods of forming transistors.