Paternal attachment styles and loneliness, as predictors of academic achievement among secondary school students in Rivers State was examined in this study. Correlational design was used for the study. Two research questions were formulated and two hypotheses were tested at 0.05 level of significance. A sample size of 513 senior secondary one (SS1) students was drawn using Taro Yemen formula. The multistage sampling technique was used to draw nine secondary schools in Rivers State. Instruments used for data collection were; Father-child Relationship Inventory (FCRI), Social and Emotional Behaviour towards Relationship Network (SEBTREN), with a Cronbach Alpha of 0.78 for (FCRI) and 0.72 for (SEBTREN). Linear regression and one way ANOVA method were used for data analysis. The study revealed that paternal attachment styles predicted students’ academic achievement. Loneliness had a moderate relationship with academic achievement. Recommendations were made that fathers should ensure that the secure attachment style dominates their child rearing practices. Fathers and teachers should at the observation of loneliness behaviour in their students consult the counsellor for therapeutic processes.