Over the past few decades, the world is moving towards miniature products owing to the technological developments in variegated industrial domains such as aerospace, biomedical, electronics, etc. This has led to the exponential growth of efficient micro cooling systems which are light in weight and have effective thermal performance. Microchannel Heat Sinks and Microchannel Heat Exchangers are the widely adopted solutions for such efficient micro cooling systems. This paper comprehensively reviews the recent developments in the field of Microchannel Heat Sinks and Microchannel Heat Exchangers. Initially, the concept of microchannel cooling is discussed. Further, a comprehensive review of materials, fabrication methods, experimental investigation, and numerical analysis is presented.