Abstract Inverted perovskite solar cells (PSCs) have become a current research hotspot due to their advantages such as low‐temperature preparation, low hysteresis, and compatibility with stacked other cells. NiO x , as a metal oxide hole transport layer material, is widely used in inverted PSCs. However, challenges such as high defect density, low intrinsic conductivity, and unfavorable valence band mismatch at the NiO x /perovskite interface hinder further improvement of device performance. Therefore, enhancing the buried interface between NiO x and perovskite layers is crucial for optimizing performance. This review systematically categorizes materials based on their types, including organic small molecules, self‐assembled monolayers (SAMs), polymers, and salts. Additionally, it incorporates other strategies, such as the introduction of low‐dimensional materials, metal doping, and advancements in NiO x deposition technology. By reviewing the materials and technologies used in the past 2 years, this article aims to provide insights for enhancing the buried interface to achieve more efficient and stable NiO x ‐based PSCs. Finally, we also discuss future directions and challenges.