<p>This study surveyed government-funded co-educational primary and junior high school students in two districts in the central region of Ghana. Students’ perceptions of their mathematics classroom learning environment and its associations with their self-efficacy and mathematics achievement were investigated. The ‘What Is Happening in This Class?’ and problem-solving disposition scales were adapted to study 221 grade&#xa0;6 students, 230 grade 7 students, and 211 grade 8 students in eight schools. Data analysis included exploratory and confirmatory factor analysis, descriptive statistics, MANOVA, and partial least squares (PLS) approach to structural equation modelling. The results showed that primary and junior high school students generally did not perceive their mathematics classroom environment favourably, their self-efficacy in word problem-solving was not encouraging, and they reported ‘sometimes’ using word problem-solving skills when learning mathematics. Significant grade differences were found in perceptions of the learning environment and self-efficacy in word problem-solving. Gender differences were insignificant on all scales. Investigations and task-orientation factors of the mathematics classroom learning environment were significantly associated with self-efficacy, problem-solving skills, and mathematics achievement. Factors of the mathematics classroom learning environment explained more variations in self-efficacy in mathematics problem-solving than any other outcome. Improving the mathematics classroom learning environment could improve students’ self-efficacy and mathematics achievement. The implication is that the learning crisis in the African context can be reduced with improved mathematical investigations in the classroom learning environment. The Ministry of Education policies could develop topic-specific mathematical investigation examples for the Ghanaian classrooms. These will be freely available to teachers.</p>