An area of potential vulnerability for U. S. forces during urban operations is the need to face an adversary's use of deception (a likely part of an overall asymmetric strategy). Significantly, deception is also an area of great potential benefit if employed effectively by U. S. forces as a core component of information operations. Drawing heavily from the historical record as well as such diverse sources as animal biology, social psychology, and criminology, this research seeks to establish a broad theoretical framework within which to consider deception. It concludes that deception is altered in form and abetted in function by the urban environment. This potentiating interrelationship between urban terrain and deception has six fundamental characteristics: (1) The scope of deceptions is greater in the urban environment than any other, (2) the abundant "background noise" of urban environments hampers counterdeception faculties, (3) cities are a rich trove of materials with which to conduct deception, (4) decisionmaking is generally worsened in urban environments relative to other environments, (5) the presence and proximity of noncombatants complicate the intelligence picture at all operational levels, and (6) urban clutter attenuates the leverage of technology. These six factors represent a considerable hindrance when facing adversary deception in built-up areas but can also be a great help to U. S. forces conducting deception in support of urban operations. These findings form the basis of ongoing work to improve U. S. capabilities for countering/employing deception in future urban operations.