Complicity is a broad doctrine that imposes criminal responsibility on individuals for a crime committed by someone else, usually because these secondary actors have intentionally helped or encouraged the primary actor to commit the crime.However, complicity also imposes responsibility based on other criminal law doctrines, such as conspiracy. In that regard, conspiracy differs from accomplice liability. In most jurisdictions, a person may be held accountable for the conduct of a co-conspirator who commits a crime in furtherance of their agreement. In the latter case, the mere existence of the conspiracy is sufficient to justify liability for the other’s conduct; therefore, assistance in commission of the crime is not required. The relevant difference between conspiracy and accomplice liability is that, while an agreement is an essential element of the crime of conspiracy, aid sufficient for accomplice liability may be given without any agreement between the parties. Accordingly, conspiracy has been adjudged a separate and distinct offense from that of aiding and abetting since it involves the additional element of preconcert and connivance not necessarily inherent in the mere joint activity common in adding and abetting.On the other hand, the concept of personal liability with regard to the accomplice liability as distinguished from vicarious liability is deeply rooted in criminal law jurisprudence. In this respect, The Anglo-American courts impute the acts of the primary party to the secondary actor. That means, once a person becomes an accomplice of another, his identity as a person subject to criminal punishment is subsumed in that of the primary party. In this research paper, we will focus on a form of complicity called accessorial or accomplice liability looking at this both legal concept as it is understood both in Egypt and in the United States. In general, individuals who help another person to commit a crime are accessories or accomplices to that offense and also liable for its commission. Moreover, statutes and case law will use terms like “aid, abet, assist, solicit…etc.”to describe the various sorts of conduct that can generate accomplice liability. There are, however,differences between the -Egyptian and American legal systems- in how they determine accomplice liability and punish those who are found to be complicit.