The 1880 Caernarvonshire by-election was a parliamentary by-election held for the House of Commons constituency of Caernarvonshire in Wales on 2 December 1880.
The by-election was caused by the resignation of the sitting Liberal MP, Watkin Williams, who was appointed as a judge of the Queen's Bench Division of the High Court of Justice.
[1] Two candidates were nominated by the two main parties of the time.
The Liberal Party nominated businessman William Rathbone.
[2] The Conservative Party nominated Welsh landowner and magistrate Hugh Ellis-Nanney.