The wind-induced response of a high-rise chimney can be divided into along-wind response and across-wind response. The along-wind responses are dominated by buffeting vibrations caused by flow turbulence. The across-wind responses are dominated by vortex-induced vibrations (VIVs) caused by Karman vortex shedding. Accurate assessment of these two kinds of wind-induced responses is critical to the wind-resistants design and structural safety of strustures. The two-dimensional wake oscillator model established by Y. Tamura is further derived and successfully applied to the three-dimensional structure in the present study. An iterative calculation method for practical engineering structures is proposed, which provides a new field of vision for VIV predictions of chimney structures. In addition, a complete quadratic combination (CQC) method in the frequency domain is developed for buffeting predictions of high-rise chimneys. The results of frequency domain calculation are compared with those of time domain calculation. The results show that the iterative calculation method can effectively predict the VIV responses of three-dimensional chimneys, and the buffeting responses calculated in the frequency domain are in good agreement with that obtained in time-domain.