Mary Kay Lanthier (born 1971) is an American lawyer who is serving as a United States district judge of the United States District Court for the District of Vermont.

- Gender
- Female
- Race
- White
Prior employment
- Rutland County [Vermont] Public Defender's Office2007–2024
- ↳staff attorney · 2007
- ↳supervising attorney · 2007–2024
- Vermont Law and Graduate SchoolAdjunct professor · 2017–2023
- Private practice, Middlebury, Vermont1998–2000, 2003–2007
- Addison County [Vermont] Public Defender's OfficeStaff attorney · 2000–2003
- Vermont Trial Courts, Chittenden and Addison CountiesLaw clerk · 1996–1998
Appointments
2024–present · Appointed by Joseph R. Biden (Democratic)
Education
J.D. · 1996- Amherst CollegeB.A. · 1993