Breaching activities are required for military operations in urban environment and for firefighters in emergency situations for saving lives. Explosive wall breaching is a key capability in military operations in urban terrain environments where the close proximity of urban structures significantly restricts the use of large demolition charges. Explosive breaching is also used by special operations groups as a means to gain entry into a structure where conventional breaching methods are not sufficient or the emergency situation requires immediate entry to save lives. This paper develops an analytical model for the explosive breaching of protective targets such as concrete and masonry walls. It provides simple analytical models based on the principles of blast physics and the conservation laws for the characteristics of contact charges required to produce a wall breach of the required shape and size. The model is validated using the experimental data. An illustrative example is included to demonstrate the model's ability to predict the size of a breach hole in a thick masonry wall.