Art therapy, as an effective therapeutic intervention, is used to improve positive self-image and self-awareness, promote insight, and enhance therapeutic communication. This study aimed to evaluate the efficacy of art psychotherapy on ego functions, emotion regulation, and interpersonal relationship styles of individuals with neurotic personality organization. Using a quasi-experimental pretest-posttest design, 60 participants were assigned to intervention and control groups, each further divided into three subgroups (n = 10 per subgroup). The intervention group engaged in online art therapy sessions twice weekly over nine weeks, while the control group received no intervention. Data analysis involved descriptive statistics, paired samples t-tests, and independent t-tests. There was a significant decrease in the intervention group's judgmental subdimensions of the Ego Function Assessment Scale. A significant decrease was found in the intervention group in “awareness” (p < 0.01), “clarity” (p < 0.05), and “impulse” (p < 0.001) subdimensions and total scores of the Difficulties in Emotion Regulation Scale. There was no statistical difference between the intervention and control groups' mean pretests and posttests and comparing those groups with each other concerning IRSQ scores. The online group art therapy led to successful improvements in participants' ego functions and emotion regulations.