Most people assume cancer diagnosis functions as a “teachable moment,” that is, a major life event that triggers a significant increase in people’s motivation to adopt healthy behaviors (e.g., regular exercise, diet high in fresh fruits/veggies) and cease unhealthy behaviors (e.g., heavy alcohol use, medication noncompliance). Conceivably, the power of cancer diagnosis to serve as a “teachable moment” should extend to smoking behavior wherein cancer patients would be expected to quit smoking immediately upon diagnosis and remain abstinent for the balance of their lives. In reality, however, cancer survivors are estimated to smoke at a rate that is equal to or greater than the general population, with subgroups of cancer survivors smoking at much higher rates (40-50%). In my work, I aim to determine if, how, and for whom cancer diagnosis does indeed function as a “teachable moment” for smoking, with a central goal of more fully understanding the naturalistic process by which smoking cessation occurs after a new cancer diagnosis. In this talk, I will examine the interplay between cancer diagnosis and smoking behavior through several different, but complementary research methods, including intensive longitudinal data collection, concurrent mixed methods, randomized clinical trials, and implementation science. Ultimately, this line of research has the goal of promoting smoking cessation among the most vulnerable cancer survivors, including those who report little to no intention to quit and those who are faced with high levels of unmet social support needs.