The Osage Nation, an Native American tribe in the United States, is the name predecessor of most other terms containing the word "osage".

Osage can also refer to:

• Osage-orange, Maclura pomifera, a tree of the mulberry family
• Osage Indian murders (1921-1923), a group of murders investigated and solved by the United States Federal Bureau of Investigation that took place on the Osage Indian Reservation
• Osage River, a tributary of the Missouri River, entirely contained in Missouri, United States

Osage is a part of many placenames in the United States, including:

• Osage, Iowa
• Osage, Oklahoma (also known as Osage City, Oklahoma)
• Osage, West Virginia (near Morgantown, West Virginia)
• Osage, Wyoming
• Osage Beach, Missouri
• Osage City, Kansas
• Osage County, Kansas
• Osage County, Missouri
• Osage County, Oklahoma
• Osage Hills State Park
• Osage Indian Reservation (*Redirect)
• Osage State Fishing Lake
• Osage Township, Illinois
• Osage Township, Minnesota
• Femme Osage (Missouri), location where Daniel Boone settled in 1799
• Fort Osage (Independence, Missouri), a United States Army base built in 1808