Objective Peaceful Living, a cognitive‐behavioral treatment (CBT) for late‐life generalized anxiety disorder (GAD), produced positive outcomes in GAD severity, anxiety, depression, insomnia, and mental health quality of life relative to usual care with treatment delivered by either bachelor‐level lay providers (BLPs) or PhD‐level expert providers (PLPs). We examined long‐term maintenance of gains during 12 months following CBT for patients in this trial who received the intervention delivered by BLPs and PLPs and completed post‐treatment assessments. Methods Participants were 112 older adults (mean age, 66.83 years) with GAD recruited from primary care who received CBT from BLPs (n = 52) or PLPs (n = 60) and completed post‐treatment assessments. Assessments were given at post‐treatment and at 6‐ and 12‐month follow‐up. Primary outcomes assessed long‐term maintenance of gains in worry (Generalized Anxiety Disorder Severity Scale) and anxiety (State‐Trait Anxiety Inventory, Structured Interview Guide for the Hamilton Anxiety Scale). Secondary outcomes assessed depression (Patient Health Questionnaire), mental health quality of life (Medical Outcomes Study Short Form – mental wellness scale), and sleep (Insomnia Severity Index). Results At 6‐ and 12‐month follow‐ups, post‐treatment reductions in GAD severity, anxiety, depression, and improvements in mental health quality of life and sleep were maintained for patients in both groups. No differences were found, based on provider group. Conclusion Treatment of late‐life anxiety delivered by nonexpert lay providers working under supervision of licensed providers has lasting benefits. These findings support the potential of new models of care for older adults that may expand reach of mental health services. Copyright © 2016 John Wiley & Sons, Ltd.