The objective of this paper is to help clarify the roles of design and construction professionals in site safety. The paper first presents the results of a survey on site safety expectations that indicate that A/Es, general contractors (GCs), and subcontractors are not uniformly agreed on which group should have primary responsibility for site safety. Next, reasons why there are not common expectations about site safety responsibilities are theorized. A causal model about construction accidents is then proposed, and factors associated with each cause are identified. Finally, the respective abilities of the entities typically involved with construction projects to influence these factors are analyzed. This analysis can be used to establish fair and practical expectations on site safety roles based on the assumption that entities that have limited abilities to prevent construction accidents should also have limited responsibility for site safety.