This thesis explores the interrelations between the design characteristics of activity-based offices, users’ perceptions of them, and users’ sense of coherence. The goal is twofold: (i) contribute to conceptualizations of healthy activity-based offices and (ii) facilitate practical use of the sense of coherence theory for office designers. Most research into healthy offices has focused on harm-causing factors (pathogenic aspects) while overlooking the health-promoting design characteristics in activity-based offices (salutogenic aspects). This thesis is a response to the call for a paradigm shift and explores the particular design characteristics of activity-based offices that promote health, drawing on the salutogenic approach and sense of coherence theory. The thesis builds on a literature review and two mixed methods case studies on activity-based offices. Drawing on the sense of coherence framework, three types of design characteristics were identified: (i) those that promote a clear understanding of office environments, (ii) those that enhance users’ access to relevant resources, and (iii) those that evoke meaning for users to cope with stressors. These characteristics and the perceptions of them are interrelated meaning that they can have multiple impacts on users’ sense of coherence. The findings also highlighted temporal changes in users’ perceptions, indicating that novelties of the new office wore off and the initial problems observed in the office environment worsened. Moreover, activity-based offices were not always perceived as intended because of suboptimal design solutions and contextual factors. In conclusion, there are no definitive answers to how to design healthy activity-based offices. Activity-based offices are complex environments and consist of many interacting aspects including the design characteristics, individuals’, and their work-related prerequisite as well as organization-related factors that influence users’ perceptions and their sense of coherence. The framework developed in this thesis may contribute to better-informed discussions about designing for sense of coherence. The thesis suggests that healthy activity-based offices should be viewed as a "moving project" that develops over time through experimentation and adaptation, with management’s involvement. Thus, a healthy activity-based office provides users resources and opportunities to codesign an environment that enables them (i) build meaningful social relationships, (ii) manage visual and acoustic distractions, (iii) read and understand workspaces, and (iv) receive support from management in their daily work.