Jacob Sager Weinstein (born January 8, 1972) is an American author, humorist, comedy writer, and screenwriter. For three years he was a staff writer for Dennis Miller Live, for which he received a Writers Guild of America award in 2001. Earlier he was a contributor to The Onion, and he has also written for McSweeney’s Internet Tendency, the North American Review, and The New Republic.

Sager Weinstein co-wrote with Matthew David Brozik three humor books: in 2005 The Government Manual for New Superheroes; The Government Manual for New Wizards in 2006; and The Government Manual for New Pirates in 2007.

Sager Weinstein is the author of the Hyacinth Series, a middle-grade fantasy trilogy about enchanted rivers under London.