Relatively little attention has been paid to the dimension of time in the design of social work interventions. Critical time intervention (CTI), an empirically supported psychosocial intervention intended to reduce the risk of homelessness by enhancing continuity of support for individuals with severe mental illness (SMI) during the transition from institutions to community living, is a model that was explicitly developed to address a timing-specific need. After describing the model and summarizing research that supports its effectiveness, this article considers examples of other time-sensitive interventions in social work and related fields and speculates on some potential advantages to such strategies. Further attention to various dimensions of timing in the design and evaluation of social work interventions is warranted.