One of the most influential factors on learner success is the classroom teaching methodology that the teacher adopts. This paper focuses on constructivism theory in relation to classroom practice. The theory is associated with the Swiss psychologist Jean Piaget (1896-1980) and Mark Baldwin (1861-1934).Sources of constructivism which include; cybernetics control theory and analysis of communication and language stimulated by computer science have also been discussed. Among the prominent people in support of constructivism are Vygotsky who introduced the social aspect of learning of constructivism and defined the zone of proximal learning according to which learners solve problems beyond their actual development level through collaboration. Bruner gave emphasis to active learning and viewed learning as a social process where learners construct new concepts based on current. Paradigms of constructivism for curriculum design, the Cognitive and social constructivism have been expounded to explain development of new knowledge. Appropriate strategies and activities for using constructivism in the classroom have been presented and a comparison between traditional and a constructivist class made. Assessment in constructivism teaching must adopt appropriate methods which include oral discussion, mind mapping, hand-on activities and pre-testing as opposed to traditional tests. The paper concludes that Constructivism has the major purpose of enabling learners construct new knowledge through multiple representation, active engagement, collaboration and inquiry with the teacher acting as a facilitator.