Julie Mary Lassa (born October 21, 1970) is an American public administrator and Democratic politician from Stevens Point, Wisconsin. She is the administrator of the Division of Agricultural Development at the Wisconsin Department of Agriculture, Trade and Consumer Protection, since 2025. She previously represented the Portage County region for 14 years in the Wisconsin Senate (2003–2017), and before that served four years in the state Assembly (1999–2003). During the Biden administration, she served as Wisconsin administrator for USDA Rural Development.

Julie Lassa was born in Stevens Point, Wisconsin, and has spent most of her life in the Stevens Point area, largely raised on her family's farm in the neighboring town of Dewey. She graduated from Stevens Point Area Senior High School and went on to attend college at the University of Wisconsin–Stevens Point; she earned a bachelor's degree in political science and public administration in 1993.

She served as the executive director of the Plover Area Business Association and as the chair of the Portage County Democratic Party.

Lassa is a member of the Heart of Wisconsin Business and Economic Alliance, Marshfield Area Chamber of Commerce and Industry, Business and Professional Women, and the Portage County, Wisconsin Business Council. Lassa was elected as a member of the Dewey Town Board from 1993 to 1994.

Lassa became active in politics during college with the Democratic Party of Wisconsin, and was president of the UW–Stevens Point chapter of Young Democrats during 1992 and 1993.

After graduating from college, Lassa went directly into elected office, winning a seat on the Dewey town board in 1993. That same year, she was elected chair of the Democratic Party of Portage County, Wisconsin. During this time, she was employed as an administrative assistant with the Plover Area Business Association, and began working as a government affairs coordinator for the Stevens Point Board of Realtors.

In 1994, at age 24, she made her first bid for election to the Wisconsin State Assembly, after 71st district incumbent Stan Gruszynski declined to run for re-election. The 71st district then comprised Stevens Point and roughly the southern half of Portage County, along with parts of northern Waushara County. Lassa faced two opponents in the Democratic primary, former Portage County district attorney William Murat and Stephens Point streets department mechanic Gary Olds. Lassa's candidacy, at age 24, received significant media attention around the state, and she proved to be a capable fundraiser, outraising her more established opponents. Lassa ultimately lost the primary by about 500 votes to William Murat, and afterwards worked to secure his victory in the general election.

Lassa was re-elected as county party chair after the 1994 election, but a few months into the 1995 term, she resigned from party leadership to accept a job as legislative aide to state representative Donald W. Hasenohrl, at the Wisconsin State Capitol.