The study was a quasi-experimental research project conducted to investigate the effect of performance assessment-driven instructions on the attitude and achievement in mathematics of senior high school students in Ghana at Ghana National College in Cape Coast. Two Form 1 science classes were used for the study and were assigned as experimental and control groups. These two classes were randomly chosen for the study. The experimental group consisted of forty-two students and control group forty students. Data was collected through the use of an open ended test in mathematics and a questionnaire on students' attitudes to mathematics. The questionnaire contained 15 Likert-type questions. The independent samples t-test was used to find the differences between the groups. The experimental group differed significantly on the post-test scores from the control group. This study identified that PA-driven instruction improved students' problem-solving abilities and increased student confidence in doing mathematics because they felt more competent in working mathematical problems.The study also explored students' attitude to mathematics through the use of a Likert-type questionnaire. The findings showed that students' attitudes toward mathematics were generally positive. It is recommended that Ghana Education Service should organise in-service training for mathematics teachers on the use of PA-driven instructions and mathematics teachers should also integrate performance assessment-based tasks in their students' exercises.