洛斯阿拉莫斯国家实验室（英语：Los Alamos National Laboratory，LANL；前称Y计划、洛斯阿拉莫斯实验室和洛斯阿拉莫斯科学实验室）是美国承担核子武器设计工作的两个实验室之一。另一个是劳伦斯利弗莫尔国家实验室（始于1952年）。该国家实验室位于新墨西哥州洛斯阿拉莫斯，隶属美国能源部，管理和运行则归洛斯阿拉莫斯****会（LANS）负责。洛斯阿拉莫斯国家实验室是世界上最大的科学和技术研究机构之一，它在****、太空探索、 可再生能源、医药、纳米技术和超级计算机等多个学科领域开展研究。

Los Alamos National Laboratory (or LANL; previously known at various times as Project Y, Los Alamos Laboratory, and Los Alamos Scientific Laboratory) is one of two laboratories in the United States where classified work towards the design of nuclear weapons has been undertaken (the other being the Lawrence Livermore National Laboratory). LANL is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security (LANS), located in Los Alamos, New Mexico. The laboratory is one of the largest science and technology institutions in the world. It conducts multidisciplinary research in fields such as national security, space exploration, renewable energy, medicine, nanotechnology, and supercomputing.