Photocatalytic processes of carbon dioxide (CO2) conversion and molecular hydrogen (H2) production could potentially address two major global challenges: greenhouse gas (GHG) mitigation and clean energy generation, respectively. During photocatalysis, the energy harvested via the light absorption in photosensitizers drives the important chemical reactions using the photogenerated charges to convert water into H2 or CO2 into value-added products. Recent decades have witnessed the widespread popularity of photocatalytic technology owing to its sustainable, renewable, and greener pathway to produce fuels and chemicals. Given this, a wide range of materials have been explored for photocatalytic applications. Among the developed materials, Ni-based photocatalysts have received considerable attention due to their distinct properties including low cost, stability, abundance, and high activity. This review addresses recent developments concerning nickel (Ni)-based photocatalysts used in photocatalytic CO2 conversion and H2 production. The use of Ni-materials plays a crucial role in enhancing photocatalytic activity through improved light-absorption, charge-separation, along with suppressed charge recombination to enhance the efficiency of hydrogen evolution and CO2 conversion. The performance of nickel-based photocatalysts during CO2 reduction and water splitting reactions is summarized, which provide a comprehensive overview of Ni-based photocatalyst efficiency and selectivity. Finally, challenges and future prospects are examined in detail for further optimization of Ni-based photocatalysts. This review also provides an update on the studies that have been conducted on Ni-based materials for H2 generation and CO2 reduction.