Photoelectrochemical (PEC) water splitting is a promising route to low-cost and large-scale green hydrogen production. The durability of the light absorbers immersed in the aqueous electrolyte solution is a major factor in the cost of the resulting hydrogen, 1,2 and much of the efforts on simple semiconductor/electrolyte junction PEC systems have shifted towards incorporating protective overlayers to minimize (photo)corrosion of the materials. The use of such overlayers aids not only the durability, but also the optoelectronic properties of the absorber layer: the photovoltage in these coated systems is generated at a solid-solid interface, and various strategies such as contact selectivity can be used to improve the photovoltage. Amorphous titanium dioxide (a-TiO2) deposited by atomic layer depositions (ALD) has been widely employed for corrosion protection of PEC materials, primarily for photocathodes, since the conduction band of a-TiO2 is close in energy to the thermodynamic hydrogen evolution potential. For smaller bandgap, high efficiency photoanode materials, the deep valence band of the a-TiO2 overlayer represents a large barrier for hole injection that could preclude charge transfer. However, a defect band in the a-TiO2 deposited by ALD was shown to enable hole transfer, and photoanode materials such as crystalline Si, GaAs, and GaP modified with a-TiO2 have demonstrated excellent performance and stability for PEC water oxidation. Despite these demonstrations of photoanode stabilization using energy intensive and/or high-cost semiconductors, the use of a-TiO2 layers on low-cost, easy-to-prepare photoanode materials such as metal oxides, has been rarely reported, likely due to high recombination at the photoanode/TiO2 interface from the relatively slow extraction of holes through the a-TiO2 defect band. While metal oxides are investigated for large scale water splitting due to their Earth abundance, ease of synthesis and perceived stability, they often suffer from (photo)corrosion, and therefore efforts have been directed towards stabilizing them. For instance, McDowell et al. used a-TiO2 as a protective layer for BiVO4 photoanodes that showed stability for several hours. However, the thickness of the protective layer was only 1 nm and charge transfer could be achieved via tunneling. For long term stability, there should ideally be no pinholes in the protective layer, and to have a good chance of achieving this, relatively thick layers of TiO2 will likely be required (>50 nm). Here, we report a hybrid polyethyleneimine (PEI)/TiO2 layer on both BiVO4 and Fe2O3 that not only protects these relatively small bandgap metal oxide photoanode materials from (photo)corrosion but also serves as a hole-selective contact. Although a PEI coating has been reported to lower the work function of semiconductor materials, in this study we embed the PEI in a-TiO2 during the ALD process by reacting the TiO2 precursor with the abundant amine functionalities of the polymer, yielding a highly defective PEI/TiO2 layer that transmits holes and blocks electrons. The BiVO4/PEI/TiO2 photoanode demonstrated an onset potential of 0.28 V vs. reversible hydrogen electrode (RHE), a photocurrent of 2.03 mA cm -2 at 1.23 vs. RHE, and stable PEC water oxidation for 120 h in pH 8 electrolyte solution.