Use of microparticulated whey protein (MWP) was patented in 1988; since then much research has been conducted on use of MWP. This review provides an overview of the use and functionality of MWP in dairy applications and discusses how MWP interacts with other components in dairy matrices. For fermented dairy products, fine-tuning of the interaction potential of MWP is of major importance. For products where MWP serves as an inert filler (e.g., cheese, ice cream), initial processing should ensure that MWP will not interact with the product matrix ensuring creaminess and desired structural weakening. Future research should focus on how raw material composition and processing affect the properties of MWP, on the role of particle characteristics on interactions with other dairy product components, and on how to develop particulated ingredients suitable for high protein products and further clarifying the role of MWP in ensuring creaminess in complex dairy matrices.