Yaƙin basasa na Cambodia yaƙin basasa ne a Cambodia wanda aka gwabza tsakanin dakarun Jam'iyyar Kwaminis ta Kampuchea (wanda aka fi sani da Khmer Rouge, wanda Arewacin Vietnam da Viet Cong ke goyon bayan) akan sojojin gwamnatin Masarautar Cambodia kuma, bayan Oktoba 1970 , Jamhuriyar Khmer, wadda ta gaji mulkin (dukkan su suna goyon bayan Amurka da Kudancin Vietnam).Gwagwarmayar dai ta kasance mai sarkakiya sakamakon tasiri da ayyukan abokan kawancen bangarorin biyu masu fada da juna.Rundunar Sojojin Arewacin Vietnam (PAVN) an tsara shi ne don kare Tushenta da wuraren tsafi a gabashin Cambodia, idan ba tare da hakan ba zai yi wahala a ci gaba da kokarin soja a Kudancin Vietnam.Da farko Yarima Sihanouk, shugaban kasar Cambodia ya amince da kasancewarsu, amma adawar cikin gida hade da China da Arewacin Vietnam na ci gaba da ba da taimako ga Khmer Rouge mai adawa da gwamnati ya firgita Sihanouk kuma ya sa ya tafi Moscow don neman mulkin Soviets. a cikin halin Arewacin Vietnam.^[86] Tsokatar da Sihanouk da Majalisar Kambodiya ta yi a cikin Maris 1970, biyo bayan zanga-zangar da aka yi a babban birnin kasar don nuna adawa da kasancewar sojojin PAVN a cikin kasar, ya sanya gwamnatin Amurka mai goyon bayan Amurka (daga baya ta ayyana Jamhuriyar Khmer) wacce ta bukaci cewa PAVN ta bar Cambodia.PAVN ta ƙi kuma, bisa buƙatar Khmer Rouge, da sauri suka mamaye Cambodia da ƙarfi.Tsakanin Maris da Yuni 1970, Arewacin Vietnamese sun kama mafi yawan arewa maso gabas na uku na ƙasar tare da sojojin Cambodia.Arewacin Vietnam ya juya wasu daga cikin mamayar da suka yi tare da ba da wasu taimako ga Khmer Rouge, ta haka ya ba da ikon abin da yake a lokacin wani karamin yunkuri.^[87] Gwamnatin Cambodia ta yi gaggawar faɗaɗa sojojinta don yaƙar Arewacin Vietnam da ƙarfin girma na Khmer Rouge.^[88]Sha'awar Amurka ce ta sa ta ba da lokaci don ficewa daga kudu maso gabashin Asiya, don kare ƙawarta a Kudancin Vietnam, da kuma hana yaduwar gurguzu zuwa Cambodia.Sojojin Amurka da na Kudu da Arewacin Vietnam sun shiga kai tsaye (a wani lokaci ko wani) a cikin fadan.{Asar Amirka ta taimaka wa gwamnatin tsakiya da gagarumin yakin bama-bamai na jiragen sama na Amurka, da taimakon kayan aiki da na kudi kai tsaye, yayin da Arewacin Vietnamese ke ajiye sojoji a yankunan da suka mamaye a baya, kuma a wasu lokuta suna shiga sojojin Jamhuriyar Khmer a yakin kasa.Bayan shekaru biyar na gwabza kazamin fada, gwamnatin Republican ta sha kashi a ranar 17 ga Afrilu 1975 lokacin da Khmer Rouge mai nasara ya yi shelar kafa Democratic Kampuchea.Yakin ya haifar da rikicin 'yan gudun hijira a Cambodia tare da mutane miliyan biyu - fiye da kashi 25 na al'ummar - sun kaura daga yankunan karkara zuwa cikin birane, musamman Phnom Penh wanda ya karu daga kimanin 600,000 a 1970 zuwa kimanin mutane miliyan 2 a 1975.