Multilayered polymer particles with a wide range of properties can be precisely engineered via the layer-by-layer technique using a multitude of templates and materials. Such multilayered particles are emerging as a powerful platform for biomedical applications. In this short review, we provide an overview of developments in the engineering of multilayered polymer particles, and describe recent progress in their utilization in biological systems. Emphasis is placed on engineering strategies that achieve different biological objectives, ranging from triggered intracellular release of therapeutics to induction of protective immunity in vivo through particle-enabled vaccination. Finally, we provide a critical outlook of the key issues associated with the continued development of multilayered particles for biological applications.