Major Depressive Disorder is common and debilitating. Individuals with depression show biases toward negative, and away from positive, information-- referred to as cognitive control biases. These lead to difficulty regulating emotions, unhealthy biological responses to stress, and ultimately, greater depression. Cognitive control biases are not adequately treated by current therapies. The objective of this clinical trial is (1) to test the effectiveness of a new cognitive control intervention (CCI) for depression and (2) to understand how it works. Participants will be assigned to a 4-week CCI group or a control group. Cognitive control biases, emotion regulation, and depression will be measured before and after CCI and 6 months later, and biomarkers of stress will be collected post-CCI. I predict that the CCI group will show improved cognitive control biases and emotion regulation, healthier biomarkers of stress, greater decreases in depression, and higher remission rates after CCI. Changes in cognitive control biases, emotion regulation, and biomarkers are expected to account for outcomes. CCI has the potential to be an accessible, virtual alternative to current therapies, and findings will inform our understanding of depression.