This study examined, "The Effects of Cooperative Learning Strategies and Attitudes on Performance in Secondary School Mathematics in the South West Region of Cameroon". The researcher's concern about the study emerged from his observations over a period of more than five consecutive years on the very poor performance of students at the General Certificate of Education, Ordinary Level. This made him to ask a number of questions, from which one general research question was formulated. This was To what extent do cooperative learning strategies and attitudes affect performance of students in secondary school mathematics This general research question gave rise to four specific research questions which were translated to a general hypothesis and four specific hypotheses respectively. A combined quasi experimental and survey research design was used for the study. The target population of the study consisted of 5,671 Form Three students in the entire South West Region. From this population, a sample of 359 Form Three students was selected for the survey study, and 65 students in their intact groups of 34 and 31 students were used for the quasi experimental study. Both probability, in particular, simple random sampling technique and the non probability sampling, in particular, purposive sampling techniques were used in the study to select the subjects. The questionnaire, pre test and post test, instrument for focus group discussion were the instruments used for data collection. Validation of the instruments was done through face, content and constructs validity. Reliability was achieved through the test re test method. The hypotheses were tested through inferential statistics. In particular, through the t test and Pearson Correlation r coefficient product moment. The results rejected all the null hypotheses while retaining their alternative forms. This led to the following conclusions 1. The mean performance of students exposed to peer tutoring in the study of mathematics is significantly better than that of those who study individually. 2. The mean performance of students exposed to positive interdependence in the study of mathematics, is significantly better than that of those who study individually. 3. There is a significant relationship between interest in secondary school mathematics and performance. 4. There is a significant relationship between participation in mathematics lesson and performance in secondary school mathematics. Based on these results, recommendations were made to teachers to regularly use cooperative learning strategies so as to raise the interest of learners and their participation in mathematics, with the results being improved performance. Nkengasu William Oben "The Effects of Cooperative Learning Strategies and Attitudes on Performance in Secondary School Mathematics in the South West Region of the Republic of Cameroon" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-1 , December 2018, URL: https://www.ijtsrd.com/papers/ijtsrd18970.pdf