This study was carried out to investigate Effective Classroom Management and Students' Academic Performance in Secondary schools in Uyo Local Government Area. Four research questions and four null hypotheses were formulated to guide the study. The survey design was adopted for the study. The population of 2044 Senior Secondary School One (SS1) students with a sample of 200 students selected from 5 public secondary schools in 4 clans within the study area. A researcher -- made questionnaire was used to elicit data from respondents. The research instrument has a 4-point rating scale and 25 items based on the study variables. The Pearson Product Moment (PPM) Correlation Coefficient of 0.94 ascertained the reliability of instrument for use in the study. After the administration, scoring and collation of the instrument, the data obtained were subjected to the chi-square (X[superscript 2]) analysis. All the null hypotheses were tested at 0.05 level of significance. Based on the result of this study, it is concluded that SS1 students in the public Secondary Schools in Uyo Local Government Area differ significantly in terms of academic performance based on verbal instruction, corporal punishment, instructional supervision, delegation of authority to learners. It is recommended that teachers should be skilled in classroom management so as to influence students' academic performance positively.