Internet abuse in the workplace refers to employee’s use of Internet provided by the organization for non-workrelated purpose. It has not only resulted in productivity loss, bandwidth waste and legal liability, it also exposed organizations’ information systems to a host of new security threats. To gain a better understanding of the factors influencing Internet abuse behavior in the workplace, this study applied the Theory of Interpersonal Behavior proposed by Triandis and investigated the effects of job satisfaction, affect, social factors, perceived consequences, habit and facilitating conditions on Internet abuse intention and behavior. Results indicated that all factors are significant at 0.05 level. Affect, social factors and habit have the greatest influence on Internet abuse intention and behavior. An interesting result is that employees with higher level of job satisfaction have a more positive affect towards Internet abuse. Implications for Internet security management are discussed.