Existing research integrity (RI) guideline development methods are limited in including various perspectives. While co-creation methods could help to address this, there is little information available to researchers and practitioners on how, why and when to use co-creation for developing RI guidelines, nor what the outcomes of co-creation methods are. In this paper, we aim to address this gap. First, we discuss how co-creation methods can be used for RI guideline development, based on our experience of developing RI guidelines. We elaborate on steps including preparation of the aims and design; participant sensitization; organizing and facilitating workshops; and analyzing data and translating them into guidelines. Secondly, we present the resulting RI guidelines, to show what the outcome of co-creation methods are.Thirdly, we reflect on why and when researchers might want to use co-creation methods for developing RI guidelines. We discuss that stakeholder engagement and inclusion of diverse perspectives are key strengths of co-creation methods. We also reflect that co-creation methods have the potential to make guidelines implementable if followed by additional steps such as revision working groups. We conclude that co-creation methods are a valuable approach to creating new RI guidelines when used together with additional methods.