William Larned Thacher (1866–1953) was an American tennis player.

[1] Thacher was a champion at Yale and semi finalist in the 1886 National Intercollegiate singles.

[2] While headmaster at the Thacher school (started by his brother) in Ojai, California, William built new tennis courts at the school and helped the game to thrive.

On his sole appearance in the U. S. Championships in 1887, Thacher beat Godfrey Brinley before losing to Howard Taylor in the semifinals.

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