Transatlantic security cooperation entered a new era after the 9/11 attacks in America, the launch of EU crisis management/security assistance operations, and the release of the European Security Strategy (ESS) in 2003. Since then, years of practical experience have inspired the EU to enhance its ambitions in this realm by developing a Cybersecurity Strategy, a Maritime Security Strategy, and most recently, the 2016 EU Global Strategy (EUGS). As these efforts respect NATO’s primary role in European defence, there is more scope for practical EU-US collaboration regarding crisis management and security assistance operations. However, although there have been some clear successes here, the EU is also increasingly willing to forge its own path in this realm and possibly diverge with US priorities. This article evaluates the recent record of, and prospects for, EU-US security collaboration regarding various problems mentioned as strategic priorities in the ESS, EUGS, and related documents.