Online writing labs (OWLs) have assisted writers since the mid-1990s. Recently, increasing interest in creating OWLs outside of North America has arisen (Gu & Ding, 2002; Paiz, 2017, 2018; Tan, 2011). This interest in OWLs specially designed to address second language (L2) writers and their particular concerns, results from an interest in starting physical writing lab services in the traditionally defined English as a foreign language context (Reichelt et al., 2013). Despite renewed interest in OWLs, neither the TESOL nor writing centers literature has kept pace, so potential OWL designers and content developers lack research-informed, practical guidance on OWL content development best practices. This article outlines five content development best practices based on a hybrid theoretical framework informed by L2 writing and writing centers theory as well as on the practical experiences of the authors, former content developers and graduate administrators of one of the world's longest continually running OWLs. These best practices encourage would-be OWL designers to consider how to maintain linguistic and global accessibility of their resources as well as ways to create value around the multilingual and multirhetorical resources of their local users. The article concludes by looking at the potential benefits of future OWL expansion outside of North America and applying these best practices for content development.