Spline may refer to:

  • Spline (mechanical), a mating feature for rotating elements
  • Spline (mathematics), a mathematical function used for interpolation or smoothing
  • Smoothing spline, a method of smoothing using a spline function
  • Flat spline, a device to draw curves
  • Spline drive, a type of screw drive
  • Spline (alien beings), fictional alien beings
  • Spline cord, a type of thin rubber cord used to secure a window screen to its frame
  • Spline, otherwise known as Star filler, is a type of plastic cable filler for CAT cable