Objectives Compassionate mind training (CMT) is an intervention that consists of a series of exercises used in compassion-focused therapy to reduce fears, blocks, and resistance toward compassion; increase the compassionate motivation of the participants for themselves (self-compassion) and for others; help them receive compassion; and finally improve the qualities related to compassion. This study aimed to test the effectiveness of an online adaptation of CMT for a French-speaking population and its influence on the variables of compassion, psychological distress, and psychological well-being. Furthermore, it aimed to explore the maintenance of these changes 1 month after the end of the program. Methods The adaptation also included the addition of pro-social guided imagery and behavioral activation not commonly included in traditional CMT interventions. The intervention involved daily exercises over a 4-week period made accessible remotely through a website. A sample from the general population was assigned by block-stratified randomization into two equivalent groups: a control group (n = 57) and an intervention group (n = 33). The self-assessment measures were carried out pre- and postintervention as well as 1 month after the end of the intervention. They included scales of anxiety, depression, stress, self-compassion, compassion, mindfulness, and psychological well-being. Results The results indicate that the intervention increased compassion in two dimensions, compassion received from others and self-compassion, and that these effects were maintained after 1 month. The intervention had a significant effect on depression, anxiety, and stress, and this effect was maintained after 1 month. Self-criticism was also reduced, but this effect was no longer significant after 1 month. Regarding emotional regulation, only the mindfulness variable was significantly increased, and the effect was significant at 1 month. Finally, with respect to psychological well-being, the variables of personal growth and positive relationships were both shown to improve, but these effects were no longer significant after 1 month.This 4-week CMT online intervention was shown to have beneficial effects on mental health indicators in a nonclinical sample. The effects were maintained after 1 month on some variables, specifically compassion, self-compassion, and mindfulness, but not all variables. The addition of pro-social exercises helped create a sense of positive relationships, but this effect was not significant after 1 month. Conclusion This research seems to indicate that CMT could be a promising avenue for remote interventions.