The Portuguese unwillingness to decolonize. In 1951, Portugal under Dr Salazar declared her African colonies as "Overseas provinces".

The alienation of Mozambican land also contributed to this war.

The exploitation of Mozambique's natural resources.

The forced growth of cotton. African farmers were expected to grow cotton on areas designated by the Portuguese colonial government.

Forced labour and contract labour systems contributed to the war of independence. Africans were required to offer labour on public works like roads, bridges, schools and health centres at very little or no pay.

High taxes also contributed to the war of liberation.

The social divisions created by the Portuguese annoyed Mozambicans and led them to war.

Brutal Portuguese rule. The Portuguese officials were very brutal while dealing with Africans. Portuguese brutality was spearheaded by the PIDE.

The failure of constitutional and peaceful means. Secondary school students had set up the NESAM in 1949. It aimed at protecting African culture but was strictly monitored by the PIDE and didn't achieve success.

Racial discrimination. The Portuguese regarded themselves as superior to Africans and lived apart from them.

Religious intolerance and under mining of African culture. The Portuguese required Africans to abandon their culture, language and norms before becoming assimilated.

Mozambicans hated the forced conscription into the Portuguese army.

The denial of human rights led the Mozambicans into war.

Africans hated the detention camps created by the Portuguese in the name of rehabilitating African labourers.

The poverty of Africans made them resort to the war of Independence.

The supply of Mozambican electricity to south Africa, moreover cheaply led to grievances and the war of liberation.

The influence of socialist countries also led to the war of liberation.

The formation of liberation movements like the FRELIMO and COREMO led to the war. These mobilised sensitised and trained the Mozambicans leading them to fight for their rights through armed struggle.

The wind of change in Africa as shown by the independence of Mozambique's neighbours- Tanganyika, Malawi, Zambia led to strong feelings of self, determination in Mozambique.

The increase of Portuguese troops in Mozambique to 50,000 by the time of the war made the Angolans feel insecure.