The installation of topsides onto fixed structures such as jacket by the float-over method has been widely utilized in offshore construction industry. This technique demonstrates significant advantages over the conventional lifting installation especially in remote areas where heavy lifting crane barges are unavailable and topside weight exceeds the lifting capacity of the floating crane. In order to ensure smooth floatover operations, the responses of the float-over barge due to waves are crucial and must be determined. In this paper, the experimental results on the scale model of float-over barge are presented, analyzed and compared with those from theoretical analysis using developed computer programs and simplified approach using frequency domain dynamic analysis. The model tests were conducted on a model following Froude scaling law with geometric scale of 1:50. Random wave sea states were specified for the test and the results are presented in terms of Response Amplitude Operators (RAOs). The model tests were conducted in a wave basin with simulated ocean environment under random waves and the dynamic responses in terms of motions of the barge were monitored during the tests. The test results were compared with theoretical values obtained from analysis and conclusions arrived at. Overall results show satisfactory agreement between model tests and theoretical analysis. Copyright © 2012 by the International Society of Offshore and Polar Engineers (ISOPE).