Bonnie Jean Garmus (born April 18, 1957 in Riverside, California) is an American author and former copywriter.

Garmus is from Seattle. She has worked as a copywriter and creative director in the US, and has lived in Switzerland and Colombia. In April 2022, her debut novel, Lessons in Chemistry, was published. The Guardian noted its "polished, funny, thought-provoking story ... it's hard to believe it's a debut". The New York Times commented on its "entertaining subplots and witty dialogue".

Lessons in Chemistry had been sold into 35 territories and has a television adaptation in production at Apple TV+ starring Brie Larson. A French translation was published under the title La Brillante destinée d'Elizabeth Zott. The book was shortlisted for the 2023 RSL Christopher Bland Prize.

Garmus is married, with two daughters, and lives in London. She enjoys open water swimming and has rowed competitively.