Kajmakčalan (Kaimakchalan) or Kaimaktsalan (Greek: Καϊμάκτσαλαν, Macedonian: Кајмакчалан) is a mountain on the border between Greece and the Republic of Macedonia. It is the southernmost and highest peak (2524 m) of a range known in Greek as the Voras Mountains and in Macedonian as Nidže. The national frontier between the two countries runs across the summit. It is the third highest peak in Greece after Mount Olympus and the fifth highest in the former Yugoslav Republic of Macedonia.
The word "Kaimaktsalan" is of Ottoman Turkish origin inspired by its white, snowy peak: kaymakçalan means 'kaimak beater'.
The peak consists of granite, gneiss and mica.
During World War I, in September 1916, the Battle of Kajmakcalan between Serbian and Bulgarian troops took place at Kajmakčalan and around the adjacent peaks, resulting in a Serbian victory. There is a small church and crypt for the Serbian soldiers who died in the battle. Near the top of the mountain, on the Greek side, there is a small church named Profitis Ilias (Greek: Προφήτης Ηλίας).