Ouachita may refer to:

In the United States:

• Ouachita, Arkansas, an unincorporated community
• Ouachita City, Louisiana, an unincorporated community
• The Ouachita Mountains in Arkansas and Oklahoma
• The Ouachita orogeny, the geologic event that raised the Ouachita Mountains
• The Ouachita River in Arkansas and Louisiana
• Lake Ouachita
• Ouachita County, Arkansas
• Ouachita Parish, Louisiana
• Ouachita National Forest in Arkansas and Oklahoma
• Ouachita National Recreation Trail in Arkansas and Oklahoma

• The Ouachita people, a Caddo group from northeastern Louisiana

• Ouachita Baptist University, a private liberal arts institution in Arkansas
• Ouachita Hills College, a missionary training college in southwest Arkansas

• Ouachita Railroad, a Class III short-line railroad headquartered in Arkansas
• Ouachita Electric Cooperative, a rural electric utility cooperative

• Ouachita creekshell, a species of mussel
• Ouachita darter, a species of darter
• Ouachita dusky salamander, a species of salamander
• Ouachita madtom, a species of catfish
• Ouachita map turtle, a species of turtle
• Ouachita pebblesnail, a species of snail
• Ouachita rock pocketbook, another species of mussel
• Ouachita shiner, a species of minnow
• Ouachita streambed salamander, another species of salamander
• Ouachita burrowing crayfish
• Ouachita fencing crayfish
• Ouachita mountain crayfish
• Ouachita river crayfish

• Wichita (disambiguation)
• Washita (disambiguation)