This study examined the effects of positive reinforcement and social skills training counseling techniques on sullenness among senior secondary school students in Kaduna metropolis, Nigeria. A quasi-experimental design, involving a pretest-posttest control group, was employed. The study's population consisted of 150 senior secondary school students who exhibited symptoms of sullenness, selected from three public senior secondary schools in Kaduna metropolis. A purposive sampling technique was used to select a sample size of 30 students (15 males and 15 females) with a high incidence of sullenness, identified through their scores on the Mood and Feelings Questionnaire (MFQ) checklist.

The study employed t-tests, one-way Analysis of Variance (ANOVA), and Analysis of Covariance (ANCOVA) statistical methods to test five null hypotheses at a significance level of alpha P ≤ 0.05. The findings indicated that positive reinforcement was effective in reducing sullenness among secondary school students (p=0.003), and social skills training counseling techniques were similarly effective (p=0.000). When comparing the two techniques, both were found to be effective (p=0.000). No significant difference in effectiveness was observed between male and female students exposed to either positive reinforcement (p=0.241) or social skills training (p=0.391).

Based on these findings, it was recommended that counselors, school psychologists, school principals, and teachers be trained in positive reinforcement and social skills counseling techniques to effectively address sullenness among secondary school students.