高级长期威胁（英语：advanced persistent threat，缩写：APT），又称高级持续性威胁、先进持续性威胁等，是指隐匿而持久的电脑入侵过程，通常由某些人员精心策划，针对特定的目标。其通常是出于商业或政治动机，针对特定组织或国家，并要求在长时间内保持高隐蔽性。高级长期威胁包含三个要素：高级、长期、威胁。高级强调的是使用复杂精密的恶意软件及技术以利用系统中的漏洞。长期暗指某个外部力量会持续监控特定目标，并从其获取数据。威胁则指人为参与策划的攻击。

APT发起方，如政府，通常具备持久而有效地针对特定主体的能力及意图。此术语一般指网络威胁，尤其是指使用众多情报收集技术来获取敏感信息的网络间谍活动，但也适用于传统的间谍活动之类的威胁。其他攻击面包括受感染的媒介、入侵供应链、社会工程学。个人，如个人黑客，通常不被称作APT，因为即使个人有意攻击特定目标，他们也通常不具备高级和长期这两个条件。

An advanced persistent threat (APT) is a set of stealthy and continuous computer hacking processes, often orchestrated by human(s) targeting a specific entity. An APT usually targets organizations and/or nations for business or political motives. APT processes require a high degree of covertness over a long period of time. The "advanced" process signifies sophisticated techniques using malware to exploit vulnerabilities in systems. The "persistent" process suggests that an external command and control system is continuously monitoring and extracting data from a specific target. The "threat" process indicates human involvement in orchestrating the attack.