This study aimed at investigating the extent to which secondary schools mathematics teachers practice to assessment models in their mathematics teaching and learning. Definitely, the study aimed at answering the following questions: (1) To what extent do secondary schools mathematics teachers practice each of the assessment models in their mathematics teaching and learning?; and (2) Are there any statistically significant differences between secondary schools mathematics teachers' practice of assessment models that can be attributed to their exposure to training? To answer these questions, the researcher developed an instrument to use in observing mathematics teaching and learning situations to overt the assessment models that are used in these situation. This instrument was face validated through a jury of mathematics education expertises, while inter rated reliability was used to check reliability. One hundred and twenty secondary school teachers were observed while teaching to record their practices of assessment models; assessment of learning, assessment for learning and assessment as learning. The data was tabulated and analysed by the researcher. The major results were: (1) The most frequent assessment model that secondary schools mathematics teachers usually use is the assessment of leaning; (2) Both assessment for learning and assessment as learning models are seldom used by mathematics teachers; (3) There were no statistically significant differences between mathematics teachers' practices of assessment models that can be attributed to their exposure to training.