Plastics are ubiquitous in our society. They are in our phones, clothes, bottles, and cars. Yet having improved our lives considerably, they now threaten our environment and our health. The associated carbon emissions and persistency of plastics challenge the fragile balance of many ecosystems. One solution is using biodegradable plastics. Ideally, such plastics are easily assimilated by microorganisms and disappear from our environment. This can help reduce the problems of climate change, microplastics, and littering. However, biodegradable plastics are still only a tiny portion of the global plastics market and require further efforts in research and commercialization. Here, a critical overview of the state of the art of biodegradable plastics is given. Using a material flow analysis, the challenges of the plastic market are highlighted, and with it the large market potential of biodegradable plastics. The environmental and socioeconomic impact of plastics, government policies, standards and certifications, physico-chemical properties, and analytical techniques are covered. The Review concludes with a personal outlook on the future of bioplastics, based on our own experience with their development and commercialization.