In this paper, sound transmission loss through double-walled orthotropic cylindrical shells based on three-dimensional elasticity theory is investigated. Hence, the purpose of this paper is to analyze the effect of the acoustic wave incidence under two different angels on sound transmission loss through the shell. The present model is a double-walled orthotropic cylindrical shell immersed in a fluid with an infinite length, whereas the acoustic plane incident waves impinge upon the shell with two different angels of θ and δ. The state space method is used to investigate the laminate approximated model along with transfer matrix approach for modeling both walls of cylindrical shell. In order to consider the two different angles of θ and δ, the corresponding wave equations have been modified according to the wave numbers. Comparing the results obtained from presents study with those of other researchers shows an excellent agreement between the results. Moreover, the effects of different parameters on sound transmission loss through the shell have been evaluated. The results show an enhancement of sound transmission loss in double-walled cylindrical shells rather than single-walled cylindrical shells particularly in high frequency range. Also, the results indicate the dependency of sound transmission loss on both of two θ and δ angels. In other word, the variety of two incident angles may cause the significant variations in sound transmission loss.