Objective The effectiveness of remotely delivered group interventions and treatments for individuals with more complex psychiatric presentations is understudied. Nevertheless, the emergence of the COVID-19 pandemic shifted such treatments from in-person to remote service delivery without the establishment of comparable effectiveness between in-person and remote delivery. The current study presents the results of a private practice's transition from in-person treatment delivery to a videoconference-delivered Dialectical Behavior Therapy (DBT)-based intensive outpatient program (IOP) for individuals with comorbid mental health and substance use disorder diagnoses in response to the pandemic. Methods Change in symptoms of depression, anxiety, and stress following completion of the IOP was compared between the in-person and videoconference groups. Results Large reductions in symptoms were found following completion of the IOP for both the in-person and videoconference groups. Furthermore, no significant differences in symptom reduction were found between the groups. Conclusion Although large-scale replication is needed, these results suggest that IOPs and other intensive group therapies delivered via videoconference may be as effective as in-person therapies, even among individuals with more complex psychiatric presentations. Providers who have transitioned group therapies to videoconference formats or are considering creating remote groups can be more confident that they are not sacrificing treatment efficacy.