Ninety-five percent of college students procrastinate (O'Brien, 2002), often leading to poor grades (van Eerde, 2003) and anxiety (Rothblum, Solomon, & Murakami, 1986). People seek to avoid aversive stimuli, therefore the more aversive a situation, the more one will avoid (Steel, 2007). This includes avoidance of a task or situation, and experiences associated with that task. Rather than changing ineffective behavior, many suppress or avoid negative experiences, often resulting in ineffective functioning (Hayes, Luoma, Bond, Masuda, & Lillis, 2006). This process, experiential avoidance, is at the core of the psychological flexibility model and is linked to psychopathology (Hayes & Gifford, 1997). Given that procrastination is an avoidant behavior, applying this model can be a useful treatment method. The current study examines the impact of a flexibility-based intervention on procrastination with college students using both EMA and questionnaire assessments. As predicted, results indicated a significant relationship between procrastination and psychological inflexibility. Following an ACT intervention, procrastination decreased, while committed action significantly increased. Moderation analyses did not indicate psychological flexibility as affecting the strength of procrastination over time. Implications for future procrastination studies using EMA are discussed.