Neo-Vygotskian theoretical learning was developed based on Vygotsky’s notions of scientific knowledge as psychological tools and teaching these tools as major instructional content. Vygotsky’s adherents challenged the validity of the theoretical assumptions of guided discovery learning and argued that this scaffolding strategy was probably not a proper way to teach students scientific knowledge. Therefore, this paper investigated the effects of these different scaffolds and learners’ metacognition on their higher-order thinking skills and task performance in mathematical learning. Eighty-four eighth grade students participated in our study. The learning sessions consisting of eight 40-minute lessons were conducted by a single teacher. The results showed that the theoretical learning group developed significantly better higher-order thinking skills and performed better than did the guided discovery learning group or the didactic learning group. Moreover, our study did not find a significant interaction between scaffolding type and metacognition, which indicated that the theoretical learning scaffold was more effective than were the other scaffolds regardless of the levels of metacognition.