The problem of multipole acoustic Logging-WhileDrilling (LWD) is analyzed. By formulating a multipole acoustic ring source at the rim of the drill collar, we model the characteristics of monopole, dipole, and quadrupole waves in the LWD environment. In particular, we analyze the feasibility of shear-wave velocity measurement using the dipole and quadrupole waves. The results show that the dipole-flexural wave, although it can attain the shear velocity in a fast formation, lags significantly behind the expected shear-wave arrival time in a slow formation. In addition, there is a strong contamination caused by the tool flexural wave traveling along the collar. In comparison, the quadrupole wave is most suited for the shear-velocity measurement. At low frequencies, the quadrupole wave travels at the formation shear velocity and is free of the tool-wave interference.