SUMMARYWeb services are emerging as a major technology for deploying automated interactions between distributed and heterogeneous applications. The accurate prediction of their quality of service (QoS) is important because their users rely on it to decide whether they meet the QoS requirement. The existing studies of QoS prediction usually assume that QoS of service activities follows certain distributions. These distributions are used as static model inputs into stochastic process models to obtain analytical QoS results. Instead, we consider the QoS activities to be fluctuating and introduce a dynamic framework to predict the runtime QoS by employing an Autoregressive Moving Average Model and QoS reduction rules. In the case study of a real‐world composite service sample, a comparison between existing approaches and the proposed one is presented, and results suggest that the proposed one achieves higher prediction accuracy.Copyright © 2014 John Wiley & Sons, Ltd.