Andon Kalchev (Bulgarian: Андон Калчев) (1910 – 27 August 1948) was a Bulgarian scientist, army officer, one of the leaders of the Bulgarian-backed Ohrana, a paramilitary formation of Bulgarians in Greek Macedonia during World War II Axis occupation. He was active outside the Bulgarian occupied area of Macedonia, under the tolerance of the Italian and German authorities which used him in their fights with rival Greek EAM-ELAS and Yugoslav Communist resistance groups. Because of his activity, he was sentenced to death by Greek military tribunal, and was executed by firing squad on 27 August 1948.
He was born in Zhuzheltsi, Ottoman Empire, today Spilia, Kastoria regional unit in Greece in 1910. After the Balkan Wars in 1913, Greece took control of southern Macedonia and began an official policy of forced assimilation which included the settlement of Greeks from other provinces into southern Macedonia, as well as the linguistic and cultural Hellenization of the ethnic Bulgarians. The Greeks expelled Bulgarian Exarchist churchmen and teachers and closed Bulgarian schools and churches. Bulgarian language (including the Macedonian dialects) was prohibited, and its surreptitious use, whenever detected, was ridiculed or punished.
Within Greece, the Macedonian Bulgarians were designated "Slavophone Greeks". After the Balkan Wars and especially after the First World War more than 100,000 Bulgarians from Aegean Macedonia and Western Thrace moved to Bulgaria. At this time the Internal Macedonian Revolutionary Organization (IMRO) began sending armed cheti into Greek Macedonia and Thrace to assassinate officials and stir up the spirit of the oppressed population. Kalchev came from a well known IMRO Bulgarian local family, which emigrated from Greek Macedonia to Balchik, Bulgaria after the Second Balkan War. Kalchev graduated at a gymnazium in Sofia and then at the Leipzig University. Later he went back to Bulgaria, where he graduated also at a military officer's school in Sofia.