This study examined relationships among regulation strategies, emotional and behavioral engagement, and academic achievement. Regulation strategies included metacognitive and motivational regulation strategies. Motivational regulation strategies have three subtypes: autonomous regulation strategies, cooperative strategies, and performance strategies. A self-reported survey was administered to 199 undergraduates from four universities, and an examination was conducted three months after the survey. Path analysis showed that use of metacognitive strategies was positively correlated with test scores, mainly through behavioral engagement. Moreover, use of autonomous regulation strategies was positively correlated with emotional engagement. Emotional engagement was positively correlated with test scores via behavioral engagement. On the other hand, use of performance strategies was negatively correlated with emotional engagement. Use of cooperative strategies was not correlated with engagement. These results indicate that each regulation strategy has a different function in learning, and that engagement mediates the relationships between various regulation strategies and academic achievement.