The boys' 50 metre butterfly event at the 2018 Summer Youth Olympics took place on 10 and 11 October at the Natatorium in Buenos Aires, Argentina.

[1] The heats were started on 10 October at 10:00.

[2] The semifinals were started on 10 October at 19:00.

[3] The final was held on 11 October at 18:48.

[4]