The basaltic caldera volcanoes in the Galápagos Islands characteristically erupt lavas via summit circumferential and radial flank dike intrusions, but the underlying magma plumbing systems remain enigmatic. Here, we document surface displacements of Wolf volcano using interferometric synthetic aperture radar (InSAR) data from 2015 to 2022. We show that Wolf volcano experienced 6‐years of continuous inflation after the 2015 eruption, followed by a shallow flank eruption in January 2022. The deformation is modeled with a vertical caldera ring‐fault and a radial dike on the southeast flank. The ring‐fault underwent opening and reverse faulting during the inflation period, and closure and normal faulting during and after the eruption. Stress interactions between the ring‐fault and the flank dike suggest the asymmetric opening of the ring‐fault promotes flank eruptions. The best‐fit deformation model differs from the previous models and offers an alternative view of how magma is fed into radial dikes during flank eruptions. Plain Language Summary The 2022 eruption at Wolf volcano in the Galápagos Islands started from a radial fissure on the SE flank, which was different from the 2015 eruption that mainly occurred inside the caldera. We track the sequence of ground deformation before, during and after the 2022 eruption using InSAR data. We find that Wolf volcano experienced continuous inflation before the 2022 eruption, followed by deflation during and after the eruption, resulting in complex ground deformation within and beyond the caldera and on the SE flank. We propose a model with ring fault slip and opening/closure to explain the observed ground deformation within the caldera. We find that opening and reverse slip of the ring fault can explain the inflation before the 2022 eruption, while closure and normal slip caused the deflation period during and after the eruption. The asymmetric opening of the ring fault changed the stresses in the volcano and promoted the occurrence of the flank eruption. Our model is different from the dike rotation model that was proposed for Fernandina volcano and may allow for improved forecasts of the location and style of future eruptions on the Galapagos Islands. Key Points Interferometric synthetic aperture radar data are used to study ground deformation before, during and after the 2022 Wolf eruption A ring fault opening/closure model fits ground deformation of the caldera well Asymmetric opening of the ring fault promotes flank eruptions at Wolf volcano