As citizen science projects develop and spread, human–computer interaction (HCI) researchers are focusing on how to improve the user experience, attract more members and amplify scientific and learning outcomes in projects with IT infrastructure (Preece, 2016). The need to design and implement user-centred technologies was one response to the high attrition rate (Nov, 2007; Nov, Arazy, and Anderson, 2011; Ponciano and Brasileiro, 2015) and the dabbling behaviour of the members who are not deeply engaged (Eveleigh et al., 2014) noted in these communities. What distinguishes the design of citizen inquiry from citizen science design is its emphasis on advancing the collaborative inquiry learning aspects of the project and supporting citizens to initiate their own investigations. Although the community design focus is on taking engagement and user experience to a greater level, it is also important to realise that we are creating community learning and inquiry spaces. The aim of this chapter is to identify some design features for engaging members in online citizen inquiry communities whilst also supporting inquiry learning within them. This may lead to a design which offers better scaffolding and offers guidance in every inquiry step to support citizen-led investigations within an engaging and sustainable environment. Given the multi-faceted nature of online citizen inquiry communities, this study is framed around four topics: online communities, inquiry learning, design and technology. The organisation of the chapter is as follows. The following section briefly introduces the four aforementioned challenging topics. We then summarise how requirements drawn from these areas were implemented on the nQuire-it platform, tested with an online citizen inquiry community (Weather-it) and compared to another community (Inquiring Rock Hunters). Next, we reflect on the design results and propose guidelines for improving community engagement and inquiry learning in similar 211citizen inquiry communities, based on the outcomes of the interventions. The last section presents conclusions from this study.