The purpose of this study was to investigate relationships among adolescents¡¦ online misrepresentation, self-disclosure, cyber-relationship motivation and loneliness. Survey study was conducted on sample consisted of 612 Taiwanese adolescents, 13-18 years of age with instruments including scales of online misrepresentation, self-disclosure, cyber-relationship motivation and of loneliness. Findings indicated that 45.9% of the respondents admit to having online deception experience while 4.4% report prevalent online misrepresentation, with those who live in Pintung, study in specific grade orwith exposure to cyber-relationship having much more online misrepresentation. In addition, not all constructs of self-disclosure, cyber-relationship motivation and loneliness are associated with online misrepresentation. Only accuracy and valence of self-disclosure, easier communication, emotional support, away from the real world and sexual partners of cyber-relationship motivation and loneliness are associated with specific constructs of online misrepresentation. Regression analyses suggested all constructs of self-disclosure in real-life as well as anonymity and emotional support of cyber-relationship motivation have moderate explanatory power for online self-disclosure, whereas accuracy and valence of self-disclosure in real-life as well as depth of control and accuracy of online self-disclosure have low explanatory power for cyber-relationship motivation, indicating that there are factors needed to be explored.