TITLE The Use of Celebrity Endorsement with the Help of Electronic Communication Channel (Instagram): Case Study of Magnum Ice Cream Thailand RESEARCH QUESTION How does the use of celebrity endorsement with the help of electronic communication channel (Social media: Instagram) affect the buying behavior of generation Y consumers in Thailand? STRATEGIC QUESTION How can marketers use this marketing technique in an effective way to increase the number of consumers? PURPOSE OF THE STUDY The purpose of this research paper is to describe the buying behavior of generation Y consumers in Thailand with regards to the use of celebrity endorsement through the electronic communication channel (Instagram). METHODOLOGY In this research study, both primary data and existing secondary data are used. A questionnaire of 436 target respondents was taken into account to answer the research question. CONCLUSION The use of celebrity endorsement through Instagram has a low effect on buying behavior of generation Y in Thailand. However, the result shows that this advertising technique easily reach to consumers and help them to know the product.