Dewey Ballantine LLP was a corporate law firm headquartered in New York City.

Dewey Ballantine underwent numerous name changes throughout its history as partners left to serve in government positions or form new firms.

This gave them entry to high financial circles, establishing a thriving law practice.

Both Henry Friendly and John Marshall Harlan II worked at the firm during this period.

On October 25, 2006, the firm announced that it would merge with the San Francisco-based, Orrick, Herrington & Sutcliffe.

The successor firm, Dewey & LeBoeuf, collapsed in May 2012 due to debt resulting from a poor partner recruiting and compensation strategy, which led to and was exacerbated by a talent exodus.