Disclosed herein are at least partially water soluble compositions for use in 3D printing. The compositions comprise a mixture of polymeric materials that can be printed using existing 3D printing devices to form a support scaffold for overhanging parts of a 3D object to be printed. The 3D object can be printed such that at least a portion of the 3D object is printed onto the support scaffold. After printing, the support scaffold can be removed from the 3D object by treatment with water, such as by immersion in water. The compositions can comprise a mixture of one or more water soluble polymers and one or more water insoluble polymers.