The n‐type semiconducting spinel zinc ferrite (ZnFe2O4) is used as a photoabsorber material for light‐driven water‐splitting. It is prepared for the first time by atomic layer deposition. Using the resulting well‐defined thin films as a model system, the performance of ZnFe2O4 in photoelectrochemical water oxidation is characterized. Compared to benchmark α‐Fe2O3 (hematite) films, ZnFe2O4 thin films achieve a lower photocurrent at the reversible potential. However, the oxidation onset potential of ZnFe2O4 is 200 mV more cathodic, allowing the water‐splitting reaction to proceed at a lower external bias and resulting in a maximum applied‐bias power efficiency (ABPE) similar to that of Fe2O3. The kinetics of the water oxidation reaction are examined by intensity‐modulated photocurrent spectroscopy. The data indicate a considerably higher charge transfer efficiency of ZnFe2O4 at potentials between 0.8 and 1.3 V versus the reversible hydrogen electrode, attributable to significantly slower surface charge recombination. Finally, nanostructured ZnFe2O4 photoanodes employing a macroporous antimony‐doped tin oxide current collector reach a five times higher photocurrent than the flat films. The maximum ABPE of these host–guest photoanodes is similarly increased. Zinc ferrite thin films prepared by atomic layer deposition exhibit slow surface electron/hole recombination during photoelectrochemical water oxidation. Nanostructuring can be used to significantly increase their photocurrent.