High-entropy nanoparticles (HE-NPs) have recently gained considerable attention owing to their potential to yield several

materials with unique characteristics due to the homogeneous mixing of fi ve or more elements. The complexity of HE-NPs

leads to electronic hybridization, lattice distortion, and sluggish diff usion eff ects, all of which contribute to their performance

and stability. The formation of HE-NPs is thermodynamically limited, particularly by enthalpic factors. To overcome

these limitations and design intricate nanostructures, wet chemistry can be employed as a relatively straightforward

synthesis method. This review provides an overview of HE-NPs, including their defi nition, thermodynamic principles, and

wet-chemical synthesis methods. It further explores the diverse range of applications of HE-NPs and examines how specifi c

nanoparticle morphologies and compositions can be tailored effi ciently using various synthesis strategies. Additionally, this

review discusses case studies presenting optimized HE-NPs for individual applications, demonstrating their high performance.

By identifying the key factors that contribute to their superior performance, this review off ers valuable insights into

future research directions for HE-NPs.