Single-use plastic bags (SUPBs) are one of the most consumed items globally and much debate has evolved around their environmental impact. However, their alternatives for shopping – e.g. cotton and paper bags – also come with an environmental footprint, and do not necessarily outperform plastic bags in all environmental categories. To identify which solution is environmentally more sustainable, the impact of SUPBs compared to their alternatives needs to be investigated under a life cycle perspective. Life cycle assessment (LCA) is a quantitative tool designed for this purpose, to assess the environmental impacts of products and services across their full life cycle including raw material extraction, production, logistics and distribution, use and end-of-life. A meta-analysis of seven LCAs published in English since the year 2010 was conducted to investigate what can be learnt from these studies, and to provide guidance to policy makers and other actors on how to interpret results from comparative LCAs on shopping bags. The report summarises the findings, including the environmental benefits and drawbacks of SUPBs compared to other bags. The report also sheds light on the benefits and challenges of LCA as a method to assess the environmental aspects of bags. Based on the learnings from this meta-analysis, the report provides guidance for experts undertaking future LCAs of plastic bags and their alternatives to improve the comprehensiveness, consistency and accuracy of the analysis.