Increasing concerns regarding human-driven effects on the biosphere have led to the development and adoption of environmentally friendly “green” composites. Unlike conventional synthetic composites, green composites are made of natural materials in either the matrix or the fiber reinforcement (or both). They are claimed to have lower negative environmental effects due to their sustainability and easier recyclability. To assess the environmental impacts associated with any product, a life cycle assessment (LCA) is needed. This literature review summarizes the individual steps undertaken in an LCA study and discusses their relevance within the field of green composites. Similarly, an outline of life cycle costing (LCC), a type of study which determines the economic implications of a product, is incorporated. Since some phases of a product’s life cycle can have significant environmental effects, parameters affecting the time-dependant degradation of green composites and their significance in LCA studies were also explored. Finally, criteria for choosing natural fibers and biopolymers for green composites in engineering applications were considered, and case studies of hemp and flax as candidates for fiber cultivation in Alberta, Canada are provided throughout.