Hajji aikin hajji ne na wajibi, kuma daya daga cikin rassan Musulunci, wanda ake yi a watan Zul-Hijja, a birnin Makka da kewaye. Hajji ba bidi'a ce ta Musulunci ba; Maimakon haka, bisa hadisai, wasu annabawa kafin Musulunci sun yi dawafi a Ka'aba. Hatta mushrikan Makka sun kasance suna aikin Hajji da dawafin Ka'aba kafin Musulunci, kuma suna da nasu hadisai kamar dawafi tsirara, wadanda Musulunci bai yarda da su ba. Wasu addinai na Ubangiji da wadanda ba na Ubangiji ba suna da ayyukan ibada kamar Hajjin Musulmi. Muddin haikalin Sulemanu ya tsira, Yahudawa suna bukatar su halarci bukukuwa uku na musamman.
Taron Hajjin dai shi ne taro mafi girma na musulmi wanda kungiyoyi daga dukkan mazhabobin Musulunci ke halarta. Alkur'ani ya gabatar da aikin Hajji a matsayin daya daga cikin ibadojin Ubangiji kuma ya kayyade watannin aikin Hajji. Kamar yadda aya ta (Hajji/27) take cewa, an wajabta wa Annabi Ibrahim (A.S) ya sanar da mutane aikin Hajji. Akwai nau'o'in aikin Hajji daban-daban, wanda aka fi sani da Hajji Tamattu'i da musulmin da ke wajen Makka da kewaye. Hajji kuwa duk da yanayin da ake ciki, ya wajaba ga kowane musulmi sau daya kawai. Aikin Hajji yana farawa ne da sanya Ihrami kuma da wannan aikin Hajji ya wajaba a kan mahajjaci kuma wasu ayyuka sun zama haramun a gare shi.
A cikin Alqur'ani akwai ayoyi da yawa game da aikin hajji kuma akwai wata sura mai suna suratul Hajj. Haka nan an ruwaito sama da ruwayoyi dubu tara dangane da aikin Hajji da hukunce-hukuncensa da ayyukansa, kamar yadda wasunsu suka ce hajjin bayan salla ya fi dukkan ibadu. Malaman addinin Musulunci sun yi kokarin bayyana falsafar aikin Hajji baya ga ayyuka na zahiri, wanda shi ne mafi muhimmanci wajen isa ga gaskiyar tauhidi da tauhidi. Tabbas aikin hajji baya ga ma'auni na addini, yana kuma da wasu bangarori da za a yi magana a cikin wadannan bayanai.