This study investigated students’ beliefs and aliteracy as predictors of senior secondary students’ achievement in poetic Literature-in-English in Ibadan, Nigeria. The study adopted the correlational survey design. Total enumeration sampling was used to select all five Local governments in Ibadan. The sample consisted of 500 SS2 students from 10 public senior secondary schools in Ibadan. Instruments used were Poetic Literature-inEnglish Achievement Test (r= 0.73), Students’ Beliefs about poetic Literature-in-English (r= 0.80), and Students’ aliteracy scale (r= 0.76). Data collected were analysed using descriptive statistics, Pearson Product Moment Correlation and Multiple regression at 0.05 level of significance. The result showed that Students’ belief about Poetic Literature-in-English (2.71) and aliteracy (2.80) were high against the threshold of (2.50). There existed a significant relationship between achievement in poetic literature-in-English and students’ aliteracy (r = 0.29), and Students’ belief (r= 0.17). Students’ beliefs and aliteracy jointly had positive effects on 2 achievement in poetic Literature-inEnglish (multiple correlation of R = .296 and multiple R = .088; F-ratio = 2 23.927); Adj. R =.084 that is 8.4% accounting for contribution to the variance. Students’ aliteracy (β = 0.36) relatively contributed to students’ achievement in poetic literature-in-English, but students’ beliefs (β = -.098) had no significant relative contribution to achievement in poetic Literature-in-English. In view of the findings, it was recommended among others that educators should adopt creative and interactive teaching approaches to bridge the gap between students’ experiences and poetic themes, and that schools should implement programmes that encourage reading for pleasure, such as poetry clubs, and reading competition.