- Apr 1 Aden becomes a British crown colony
US Masters Golf
Apr 4 4th Augusta National Invitation Tournament (Masters) Golf: Byron Nelson wins first of his 5 major titles by 2 strokes ahead of Ralph Guldahl

Byron Nelson
- Apr 12 Sir Frank Whittle ground-tests the first jet engine designed to power an aircraft at Rugby, England.
- Apr 15 Stanley Cup Final, Olympia Stadium, Detroit, MI: Detroit Red Wings beat New York Rangers, 3-0 for a 3-2 series win; back-to-back titles for Red Wings
- Apr 19 41st Boston Marathon won by Walter Young of Canada in 2:33:20
- Apr 22 NYC college students stage 4th annual peace strike
- Apr 26 German Luftwaffe destroys Basque town of Guernica in Spain
- Apr 27 1st US social security payment made
- Apr 28 1st animated cartoon electric sign displayed (NYC)
- Apr 28 1st commercial flight across Pacific operated by Pan Am
- Apr 30 The Philippines holds a plebiscite for Filipino women on whether they should be extended the right to suffrage; over 90% would vote in the affirmative