| Election Name: | 1938 Kinross and Western Perthshire by-election |
| Type: | parliamentary |
| Country: | United Kingdom |
| Seats For Election: | Constituency of Kinross and Western Perthshire |
| Ongoing: | no |
| Previous Election: | 1935 United Kingdom general election |
| Previous Year: | 1935 |
| Election Date: | 21 December 1938 |
| Candidate1: | William McNair Snadden |
| Image1: | UP |
| Party1: | Unionist Party (Scotland) |
| Popular Vote1: | 11,808 |
| Percentage1: | 52.94% |
| Swing1: | 8.3% |
| Candidate2: | Katharine Stewart-Murray |
| Party2: | Independent (politician) |
| Popular Vote2: | 10,495 |
| Percentage2: | 47.06% |
| MP | |
| Posttitle: | Subsequent MP |
| Before Election: | Katharine Stewart-Murray |
| Before Party: | Unionist Party (Scotland) |
| After Election: | William McNair Snadden |
| After Party: | Unionist Party (Scotland) |
| Turnout: | 66.6% (6.7%) |
| Map Size: | 200px |
| Next Election: | 1945 United Kingdom general election |
| Next Year: | 1945 |
The 1938 Kinross and Western Perthshire by-election was held on 21 December 1938. The by-election was held due to the resignation of the incumbent Unionist member of parliament Katharine Stewart-Murray, Duchess of Atholl, who resigned the Conservative and Unionist whip at Westminster as a protest against the National government led by Neville Chamberlain and his European policy of appeasement of the fascist dictators Hitler and Mussolini, seeking re-election as an Independent. However, the seat was regained for the Unionists by William McNair Snadden.[1]