This study is devoted to evaluating the security risk analysis and management in Online Banking transactions using Diamond Bank PLC, Nigeria among other banks. In this paper, a research was carried out in order to evaluate the security risk analysis and management in online banking transactions through the use of the questionnaire to determine the level of risk that customers of financial institutions are likely to encounter. The study indication shows that awareness need to be intensified in terms of risk associated with clients saving password and other transaction details in their devices used in performing an online transaction. Also, the bank should improve on their banking transaction application in order to maintain integrity in view of customer account information.