SP-350 may refer to:

• SP-350 Denise, a small submarine designed to hold two people capable of exploring depths of up to 400 metres invented by Jacques-Yves Cousteau
• SP-350 (Brazil), a State highway in Brazil
• Olympus SP-350, 8-megapixel compact digital camera
• USS Roselle (SP-350), a ship that served both as a tug and as minesweeper

• Singleton Park
• Singleton railway station (Lancashire)
• Singleton railway station (West Sussex)
• Singleton Report
• Singletons Mill
• Singletons Mill, New South Wales
• Singleton, Western Australia
• Singleton, West Sussex
• Singleton West Sussex)railway station
• Single Top 100
• Singletrac
• Single Trac
• Single track
• Single-track
• Singletrack (magazine)
• Single Track Mind
• SingleTrackMind
• Singletrackmind
• Single track (mountain biking)
• Single-track railway
• Single-track roads
• Single-tranche CDO
• Single Transferable Vote
• Single transferable vote system
• Single Transferable Voting