The Greek–Serbian Alliance of 1913 was signed at Thessaloniki on 1 June 1913, in the aftermath of the First Balkan War, when both countries wanted to preserve their gains in Macedonia from Bulgarian expansionism. The treaty formed the cornerstone of Greek–Serbian relations for a decade, remaining in force through World War I until 1924.

Greece and Serbia enjoy close diplomatic relations, which have traditionally been friendly due to cultural, religious and historical ties between the two nations.