John Robert Kirtley (born August 27, 1949[1]) is an American condensed matter physicist and a consulting professor at the Center for Probing the Nanoscale in the department of applied physics at Stanford University.

His PhD topic was inelastic electron tunneling spectroscopy, with Paul Hansma as his thesis advisor.

He was then a research assistant professor at the University of Pennsylvania from 1976 to 1978, working in the group of Donald N. Langenberg on non-equilibrium superconductivity.

The citation was for "using phase-sensitive experiments in the elucidation of the orbital symmetry of the pairing function in high-Tc superconductors".

Kirtley, Tsuei, and co-workers used scanning SQUID imaging of the half-integer flux quantum effect in tricrystal samples[4] [5] to demonstrate that cuprate high temperature superconductors have predominantly d-wave pairing symmetry.