Abstract This paper examined the effect of teachers' motivational factors on the achievement of classroom teaching effectiveness in public secondary schools in Nigeria. A survey research design was used for the study. The respondents were 200 qualified teachers, both males and females randomly selected from 10 public secondary schools in Agege Local Government area of Lagos Nigeria. The research instrument for the study was the questionnaire titled Teachers' Motivation Questionnaire (TMQ). The data collected were analyzed using percentage and Pearson Product Moment Correlation Coefficient (r-test) at 0.05 level of significance. The findings showed that if teachers are adequately motivated, they would discharge their duties in the classroom efficiently and effectively. Based on the findings, it was recommended that to ensure classroom teaching effectiveness, a teacher needs not only adjustment and regular payment of salaries and allowances, but the right technology and facilities for efficiency and effective classroom management. Government, parents, and the society were also asked to assist by providing motivational incentives such as housing, car loans, and subsidized health care services as well as organizing skill-development seminars and workshops for teachers. Teaching personnel should be led and not bossed to be effective and efficient. Keywords: Motivational factors, achievement, classroom, teaching effectiveness