This chapter envisions human implications of technology in cities, i.e., urban informatics, and focuses on related sustainability issues in technology design that particularly could influence citizens’ subjectively experienced security in urban environments. To date, much of the related urban informatics research contributes either to sustainability issues or security issues in the given context. In addition, sustainable technology design is quite often seen from the economic or environmental perspectives of sustainability and the challenges of secure technology, such as network stability and functionality. However, we argue here that these two phenomena, sustainability and citizen’s experienced security, are intertwined in the context of urban informatics. Thus, this chapter reviews the theoretical approaches and considerations of current urban informatics research related to sustainability and security issues from the citizen perspective. The outcome of this study reveals the gaps that have been unrecognized and discusses future research directions. The main contributions of this chapter are framing urban informatics into broader contexts of social sustainability and experienced security.