There are many theories in psychology that are related to different schools of psychology such as cognitive, humanistic, behavioristic, etc. These theories are propounded by eminent psychologists to provide a framework to understand different aspects of human behavior.'Lev Vygotsky', a Soviet psychologist, has propounded the "Socio-cultural Theory". This theory implies the idea that social interaction plays a crucial role in the learner's development. Important PointsFrom the above-mentioned information, it is clear that the teaching-learning process is based on Lev Vygotsky's Socio-cultural Theory.According to Vygotsky, social interaction is the primary cause of learners' development as his theory emphasizes that children learn through interaction and collaboration with skilled peers and knowledgeable people. Lev Vygotsky emphasizes the importance of more skilled peers to support and guide the other students by introducing three concepts which are as follows:More Knowledgeable Other(MKO)It refers to a person with a higher skill level and a better understanding of the concepts than the learners.ScaffoldingIt refers to a process through which temporary support is imparted to the learners to enhance learning to achieve goals.Zone of proximal development(ZPD)It refers to the difference between what a learner can do on his/her own and what he/she can do with help and guidance. Hence, we can conclude that the teaching-learning process is based on Lev Vygotsky's Socio-cultural Theory.Additional InformationLawrence Kohlberg's development theory: Lawrence Kohlberg, an American psychologist, has propounded the 'Theory of Moral Development'. He has made a systematic study of moral development in his theory that is categorized into 3 levels and 6 stages.Jean Piaget's cognitive development theory: Jean Piaget, a Swiss psychologist, has made a systematic study of cognitive development in his theory that is categorized into four stages. Howard Gardener's multiple intelligence theory: The Theory of Multiple Intelligence which consists of eight different kinds of intelligence is propounded by an American psychologist 'Howard Gardner'.