Big Windup! (Japanese: おおきく振りかぶって, Hepburn: Ōkiku Furikabutte), often shortened to just Ōfuri (おお振り), is a Japanese baseball-themed manga series written and illustrated by Asa Higuchi. It has been serialized in Kodansha's seinen manga magazine Monthly Afternoon since September 2003, with its chapters collected in 36 tankōbon volumes as of December 2022.

It was adapted into an anime television series, directed by Tsutomu Mizushima and animated by A-1 Pictures, which aired for 25 episodes on TBS from April to September 2007. A 13-episode second season was broadcast from April to June 2010. In North America, the first season was licensed by Funimation, while the second season was licensed by Right Stuf.

By November 2019, the manga had over 15 million copies in circulation. It won the Tezuka Osamu Cultural Prize for best creative work in 2006 and the Kodansha Manga Award for general manga in 2007. The anime series has been overall well received by critics, who have praised its story and characters, and particularly its focus on strategy and teamwork. The series, however, has received somewhat mixed response due to its pacing.