Rubuta ci gaba don wannan sakin layi - Bayan da Nazi Jamus ta haɗu da Austria a 1938, Yugoslavia ta raba kan iyaka tare da Reich na Uku kuma ta fuskanci matsin lamba yayin da maƙwabtanta suka haɗu da ikon Axis. A watan Afrilun 1939, Yugoslavia ta sami iyaka ta biyu tare da Italiya lokacin da wannan ƙasar ta mamaye kuma ta mamaye makwabciyar Albania. Da aka soma Yaƙin Duniya na II, gwamnatin Yugoslavia ta sanar da tsakatsakinta. Tsakanin Satumba da Nuwamba 1940, Hungary da Romania sun shiga Axis, kuma Italiya ta mamaye Girka
daga Albania. Tun daga wannan lokacin, ƙasashen Axis da kuma ƙasashen da suke ƙarƙashin su sun kewaye Yugoslavia gabaki ɗaya, kuma matsayinta na tsaka tsaki game da yaƙin ya shiga matsi sosai. A ƙarshen Fabrairu 1941, Bulgaria ta shiga Axis. Washegari, sojojin Jamus sun shiga Bulgaria daga Romania, kusan rufe zoben da ke kewaye da Yugoslavia. Tare da manufar tabbatar da kudancinsa kafin harin da ke jiran Soviet Union, Adolf Hitler ya fara matsa lamba ga Yugoslavia don shiga cikin ikon Axis. Gwamnatin Yugoslavia ta sanya hannu a kan yarjejeniyar Tripartite Pact, kayan aikin da ya zama Axis bayan wani jinkiri, a ranar 25 ga Maris, 1941. Kwana biyu bayan haka, wasu 'yan kungiyar sojojin sama na Serbia masu kishin kasashen yammacin duniya sun hambarar da Yarima Paul a cikin juyin mulkin da ba a zubar da jini ba. 'Yan makircin sun ayyana Yarima Peter mai shekaru 17 da haihuwa kuma sun kawo gwamnatin haɗin kan ƙasa karkashin jagorancin Janar Dušan Simović. Juyin mulkin ya fusata Hitler, wanda ya ba da umarnin mamaye Yugoslavia wanda ya fara a ranar 6 ga Afrilu, 1941.