The magnetic order and critical behavior of well‐defined (100)p(1×1) surfaces of ultrathin (1–7 monolayers) vanadium films deposited on atomically clean and flat Ag(100) substrates is studied by electron capture spectroscopy, a novel method which probes electron spin polarization (ESP) at the topmost surface. For all investigated films, the long‐ranged ESP is nonzero, demonstrating the existence of long‐ranged ferromagnetic order at the film surface. For a 5‐monolayer‐thick film, ferromagnetic order sets in at a critical surface temperatureTCs=475.1 K. In the temperature range from 200 to 475.1 K, the ESP of the topmost surface layer follows the power law (TCs−T)β, with β=0.128±0.01. This result is in good agreement with the exact value β= (1)/(8) of the two‐dimensional Ising model.