Psychological well-being is highly important in the lives of in-school adolescents to function well generally and academically. Children solely raised by mothers without a father-figure usually become delinquents and suffer from maladaptive behaviour. This study however examined the moderating effect of parental socio-economic status and resilience on psychological well-being of in-school adolescents from father-absent families in Ekiti State, Nigeria. This study adopted the pre-test post-test control group quasi- experimental design of 3x3x3 factorial matrix. Simple random technique was used to select one Local Government Area (LGA) from each of the three senatorial districts in Ekiti State, while one Senior Secondary School (SSS) was randomly selected from each LGA. The Father-Absence Involvement Screening Scale was used to select 166 senior school I and II students across the three schools. Participants were randomly assigned to Cognitive Restructuring (CR-57), Problem-Solving (PST-59) and control (50) groups. Treatment lasted 10 weeks. Instruments used were Ryff’s Psychological Well-Being (α = 0.84), and Resilience (α = 0.83) scales, and Parental Socioeconomic Status Questionnaire (α = 0.73). Data were subjected Analysis of covariance and Multiple classification analysis at 0.05 level of significance. There was a significant main effect of parental socioeconomic status on psychological well-being (F [2;140] =4.67; partial, η2=0.063) of in-school adolescents from father-absent families. Participants with high parental socioeconomic status have higher psychological well-being ( =148.64) than their counterparts (moderate and low parental socioeconomic status). There was no significant main effect of resilience on psychological well-being (F [2;140] =1.98; partial, η2=0.028) of in-school adolescents from father-absent families. Parental socio-economic status has effect on psychological wellbeing of in-school adolescents and has moderate effect of treatment in enhancing psychological wellbeing of in-school adolescents from father-absent families in Ekiti State, Nigeria. Resilience on the other hand does not moderate the effect of treatment in enhancing psychological wellbeing of in-school adolescents. It is recommended that socio-economic status and resilience should be manipulated positively in a way to contribute to psychological wellbeing of in-school adolescents from father-absent families. Keywords: Father-absent families, Psychological well-being, In-school adolescents, Parental socio-economic status, Resilience,