The instructor of a large, introductory computer science (CS) course at a public Canadian university implemented two interventions designed to support students’ academic success and basic psychological needs as posited by self-determination theory (SDT). Interventions involved providing grading scheme choice for all students and sending targeted support emails to students who struggled on early term assessments. In keeping with SDT, we assessed the possible effect of these interventions on students’ perceptions of competence (self-efficacy), autonomy, relatedness (via measures of instructor warmth), and final grades, by comparing the intervention cohort with a previous control cohort. Results indicate that all students in the intervention term may have benefited from grading scheme choice, as they earned higher final grades and felt more autonomous than the control group students. Moreover, struggling students who received support emails earned an average final grade 11.3% higher than struggling students in the control term. These students also performed closer to their non-struggling counterparts than those in the control group; reducing the achievement gap between early struggling and non-struggling students by 8.1%. Furthermore, even when controlling for past achievement, perceptions of self-efficacy and autonomy support positively predicted students’ final grades across groups, with a small effect size. These results offer theoretical and practical insight into effective, light-touch teaching interventions which CS instructors can implement in large courses.