ABSTRACT The goal of this study was to understand how mindful awareness, acceptance, and values-consistent action change across acceptance-based behavioral therapy (ABBT) for generalized anxiety disorder (GAD) and determine their effect on symptoms. We examined weekly data from 31 individuals who received ABBT as part of a randomized control trial for individuals with GAD (Hayes-Skelton, Roemer, & Orsillo, 2013). Participants answered questions weekly about three components of ABBT, including the percentages of time they spent over their past week: 1) aware of the present moment, 2) accepting of their internal experiences, and 3) engaging in values. GAD symptoms were examined using two self-report measures (DASS-21 Stress subscale and PSWQ) and two clinician-rated interview measures (CSR and SIGH-A) at pre- and post-treatment. 1 Mindful awareness, acceptance, and values-consistent action increased linearly across ABBT. All three change trajectories were positively correlated (Z’s 2.99 to 8.74, p’s < .001). Mindful awareness, acceptance, and values-consistent action across treatment predicted decreases in GAD symptoms above and beyond baseline for most outcome measures (Z’s −1.95 to −3.03, p’s < .05), with the exception that mindfulness did not predict DASS-stress (Z = −1.39, p = .17). These findings are consistent with the structure and model of ABBT.