Analytical solutions are presented for the torsional response of piles embedded in elastic soil that is either homogeneous or where the stiffness is proportional to depth. The solutions are extended to more general variations of soil stiffness with depth and to cover behavior after peak shaft adhesion between pile and soil. Full scale torsion load tests are studied, and an analogy is suggested between the behavior of piles subjected to torsion loading and that of long compressible piles subjected to axial loading.