Decisions made in early phases of the product innovation process heavily influence the sustainability performance of a product. This study presents a literature review of approaches for assessing product sustainability performance in early phases and identifies and analyses six main challenges and opportunities from a strategic sustainability perspective: (i) finding the right combination between qualitative and quantitative approaches; (ii) avoiding reductionism; (iii) managing trade-offs; (iv) conceptualizing and defining sustainability; (v) thinking strategically; and (vi) considering both negative and positive impacts. The review also found that the terms assess, evaluate, and measure are all used in relation to sustainability performance. Based on an analysis of semantics and etymology, the study describes differences between the terms and how they should be used, arguing that assess and evaluate are more suitable when describing sustainability performance, while measure can be used in relation to indicators that can form part of an assessment or evaluation.