Secondary loads associated with typical composite structure design and corresponding laminate failure modes are discussed in this paper. The significance of these failure modes and critical environmental conditions corresponding to each failure mode are emphasized as a key to predicting an initial failure for composite structures. The most common examples of interlaminar shear and interlaminar tension failure modes due to out-of-plane loads are presented. Hole elongation and subsequent composite bolted joint stiffness reduction due to the bearing loads will also be discussed.