Jackalyne Pfannenstiel (September 7, 1947 – April 26, 2017) served as the United States Assistant Secretary of the Navy (Installations and Environment) from March 5, 2010.

In 1980, she moved to the Pacific Gas and Electric Company, initially working in utility rate setting and other regulatory matters.

The next year, she participated in the process that led to the creation of California's regulations designed to promote energy efficiency.

On April 20, 2004, Governor of California Arnold Schwarzenegger appointed Pfannenstiel to a four-year term as a member of the California Energy Commission, a board with responsibility for power plant licensing, building and appliance efficiency standards, and energy policy development.

President of the United States Barack Obama nominated Pfannenstiel as Assistant Secretary of the Navy (Installations and Environment).