新帝国主义（New Imperialism）是十九世纪晚期至二十世纪初欧洲各国（主要包括大英帝国、法兰西第三共和国、德意志帝国、奥匈帝国、意大利王国等），及后来的美国及日本以其科技及经济力量，对亚洲、非洲进行殖民地及经济势力扩张的行为。在1870年普法战争后至第一次世界大战前的四十多年间，是其发展最快的时期。英国史学家霍布斯邦对新帝国主义作出精确的时间段限，他把1875-1914年定义为「帝国的年代」，强调欧洲人因为1873-1896年间严重的经济萧条，为了纾缓经济困难，大幅向亚非地区殖民，以获取殖民地的原料和市场，并提供本国人急需的就业机会。

The New Imperialism (sometimes Neoimperialism or Neo-imperialism) was a period of colonial expansion—and its accompanying ideologies—by the European powers, the United States of America and the Empire of Japan during the late 19th and early 20th centuries. The period is distinguished by an unprecedented pursuit of overseas territorial acquisitions. At the time, states focused on building their empires with new technological advances and developments, making their territory bigger through conquest, and exploiting their resources.