Posttraumatic stress disorder (PTSD) is maintained, in part, by avoidance of external stimuli that elicit trauma-related emotions, thoughts, and sensations. In vivo exposure involves directly confronting avoided stimuli in real life to facilitate new learning about the likelihood and severity of aversive outcomes. In vivo exposure is a core procedure of the DBT Prolonged Exposure protocol (DBT PE) for PTSD and is typically used to target avoidance of situations perceived as dangerous, trauma reminders, cues that elicit unjustified trauma-related shame, and activities avoided due to depression. However, in vivo exposures can take countless forms and, to be most effective, must be creatively tailored to the specific beliefs of each client. This webinar will go beyond the basics of in vivo exposure to discuss the finer points of how to effectively design and implement in vivo exposures for particular clients. In vivo exposure optimization strategies based on inhibitory learning theory will be discussed, such as expectancy violation, deepened extinction, occasional reinforced extinction, removal of safety signals, variability, and multiple contexts. Clinical examples will be used to illustrate how to apply in vivo exposure to a variety of avoided trauma-related situations and emotions to help clients get the most out of treatment.