Critical thinking (CT) is an essential competency for global citizens in the 21st century. Few systematic reviews have evaluated and analyzed instructional interventions to enhance CT in mathematics at the university. This study includes 15 studies on cultivating CT among undergraduate students through instructional interventions within the mathematics curriculum. Quantitative and qualitative methods were employed to provide information and feedback on study and intervention characteristics, analyze the features and effects of multiple interventional strategies, and assess instruments by coding categories. The results indicate that it is essential for instructors to identify the specific CT objectives, including features, criteria, and standards of CT, before intervention. Several teaching strategies are alternatives for developing undergraduate students' CT abilities through the mathematics curriculum; however, flexibility and availability are necessary to allow students and instructors to adapt and coordinate. Further, multiple assessment instruments are essential for the instructional intervention.