This study aimed to capture and operationalize the concept of participation among people who are very old (age > 80) and to investigate whether and how aspects of housing and neighborhood environments relate to participation in very old age. Two dimensions of participation—performance-oriented participation and togetherness-oriented participation—emerged from an earlier qualitative study and were operationalized and validated in this study with quantitative variables. Both objective and perceived housing and neighborhood aspects were significantly related to, in particular, performance-oriented participation and, to a lesser extent, to togetherness-oriented participation. Most interventions in occupational therapy are accomplished within the home for very old people, but our results imply that there are potential interventions to accomplish on a societal level as well. In this respect, our study contributes to the knowledge in the field and has the potential to support the development of novel occupational therapy interventions targeting society at large.