This letter outlines the analogy which exists between inviscid jets and elastic columns in axial compression. It is shown that straight inviscid jet columns possess the property of sinusoidal infinitesimal buckling. The buckling wavelength scales with the transversal dimension of the jet. The repeated buckling and breakup of the jet column is responsible for the observed whiplash motion of turbulent jets. The buckling theory predicts correctly the natural frequency of the whiplash motion and the Reynolds number for the laminar-turbulent transition in free jet flow. © 1981.