We report on the dc susceptibility of the insulating spin glass Rb2Cu1−xCoxF4, withx=0.22. This model compound is a realization of the two‐dimensional short‐range Edwards–Anderson model, which has competing nearest‐neighbor Ising interactions. Below a frequency‐dependent freezing temperature spin‐glass behavior is observed for longitudinal spin components only. The nonlinear part of the susceptibility is found to excellently obey staticTc=0 scaling with &bgr;=0.0±0.1 and &Dgr;=3.2±0.2, in conformity with the Monte Carlo results for the two‐dimensional Edwards–Anderson model,Tc=0, &bgr;=0, and &Dgr;=3.5±0.5. These findings thus provide experimental evidence for the lower critical dimensionality for Ising spin glasses to exceed 2.