William Stemmyer (May 6, 1865 – May 3, 1945) was a Major League Baseball pitcher for the Boston Beaneaters and Cleveland Blues.

[1] In 1886 – his first and only full season in the majors – Stemmyer led the National League in strikeouts per 9 innings (6.17) and wild pitches (63).

[2][3] The 63 wild pitches is still the highest single-season total in National League history.

Stemmyer died in his hometown at age 79.

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