Islamic military jurisprudence refers to what has been accepted in Sharia (Islamic law) and Fiqh (Islamic jurisprudence) by Ulama (Islamic scholars) as the correct Islamic manner, expected to be obeyed by Muslims, in times of war. Some scholars and Muslim religious figures describe armed struggle based on Islamic principles as the lesser jihad.

The first military rulings were formulated during the first century after Muhammad established an Islamic state in Medina. These rulings evolved in accordance with the interpretations of the Qur'an (the Islamic Holy scriptures) and Hadith (the recorded traditions, actions (behaviors), sayings and consents of Muhammad). The key themes in these rulings were the justness of war (Harb), and the injunction to jihad. The rulings do not cover feuds and armed conflicts in general.

Jihad (Arabic for "struggle") was given a military dimension after the oppressive practices of the Meccan Quraish against Muslims. It was interpreted as the struggle in God's cause to be conducted by the Muslim community. Injunctions relating to jihad have been characterized as individual as well as collective duties of the Muslim community. Hence, the nature of attack is important in the interpretation—if the Muslim community as a whole is attacked jihad becomes incumbent on all Muslims. Jihad is differentiated further in respect to the requirements within Muslim-governed lands (Dar al-Islam) and non-Muslim lands, both friendly and hostile.

According to Shaheen Sardar Ali and Javaid Rehman, both professors of law, the Islamic military jurisprudence are in line with rules of modern international law. They point to the dual commitment of Organisation of Islamic Cooperation (OIC) member states (representing most of the Muslim world) to Islamic law and the United Nations Charter, as evidence of compatibility of both legal systems.

Fighting is justified for legitimate self-defense, to aid other Muslims and after a violation in the terms of a treaty, but should be stopped if these circumstances cease to exist. War should be conducted in a disciplined way, to avoid injuring non-combatants, with the minimum necessary force, without anger and with humane treatment towards prisoners of war.

During his life, Muhammad gave various injunctions to his forces and adopted practices toward the conduct of war. The most important of these were summarized by Muhammad's companion and first Caliph, Abu Bakr, in the form of ten rules for the Muslim army:

O people! I charge you with ten rules; learn them well! Stop, O people, that I may give you ten rules for your guidance in the battlefield. Do not commit treachery or deviate from the right path. You must not mutilate dead bodies. Neither kill a child, nor a woman, nor an aged man. Bring no harm to the trees, nor burn them with fire, especially those which are fruitful. Slay not any of the enemy's flock, save for your food. You are likely to pass by people who have devoted their lives to monastic services; leave them alone.

According to Tabari, the ten bits of "advice" that Abu Bakr gave was during the Expedition of Usama bin Zayd. During the Battle of Siffin, the Caliph Ali stated that Islam does not permit Muslims to stop the supply of water to their enemy. In addition to the Rashidun Caliphs, hadiths attributed to Muhammad himself suggest that he stated the following regarding the Muslim conquest of Egypt that eventually took place after his death: