The 10 NATO Member Countries With the Largest Active Military Forces

As Russia’s war with Ukraine continues, NATO remains a key focus in discussions about the conflict.

The ongoing war has accelerated NATO’s expansion. Formed in 1949 to ensure peace and security in the North Atlantic region, NATO has recently seen Finland join in 2023 and Sweden on the verge of joining by February 2024, following a long delay in approval from Hungary. With Sweden’s anticipated accession, NATO will consist of 30 European countries and two North American nations. In February 2024, NATO gained attention when former U.S. President Donald Trump controversially suggested he might challenge its fundamental principle.

Central to NATO’s mission is Article 5, which states that an attack on one member is considered an attack on all. Although Article 5 has only been invoked once—following the September 11, 2001 attacks on the U.S.—its activation is not automatic and requires unanimous agreement from all member countries. NATO does not possess its own standing army; instead, it relies on member nations to provide and support military operations, with each member committed to spending at least 2% of their GDP on defense.

To assess which NATO members have the largest active armed forces, U.S. News reviewed data from the International Institute for Strategic Studies’ The Military Balance report, which provides an annual evaluation of military capabilities across 173 countries. According to the most recent 2023 report, the following 10 NATO countries have the largest active military forces, with one country alone accounting for over a third of the total.