Life cycle assessment (LCA) is used for the comprehensive environmental assessment of engineered nanomaterials (ENMs) and ENM-enabled products. A complete LCA can highlight a possible shifting of burden where reduction of environmental impacts at one stage may come at the expense of another. The objective of this chapter is to familiarize the reader with LCA as a methodology in the context of ENMs. This is done by first presenting a basic LCA framework, followed by peer-reviewed LCAs on ENMs. We conclude with a brief on evolving approaches that address ENM-specific challenges for LCAs. © 2014 Woodhead Publishing Limited. All rights reserved.