A healthy research environment is fundamental to good science. However, this is an aspect that is rarely discussed. That’s partly because a lab’s “health” is complex and difficult to assess – it is the product of a whole host of factors, such as inclusivity, communication, expectations and training. In this special Nature issue, multiple authors explore how the working environment shapes research quality and morale – and what can be done to strengthen the research enterprise. From a survey of more than 3,000 researchers to first-hand experiences of how to nurture and improve research culture, the authors unpick the issues that can derail a lab and that can help make it the best place to work.