Qisas or Qiṣāṣ (Arabic: قِصَاص, romanized: Qiṣāṣ, lit. 'accountability, following up after, pursuing or prosecuting') is an Islamic term interpreted to mean "retaliation in kind", "eye for an eye", or retributive justice. In classical/traditional Islamic law (sharia), the doctrine of qisas provides for a punishment analogous to the crime.

The principle of qisas in ancient societies meant that the person who committed a crime or the tribe he belonged to was punished in the same way as the crime committed. That is, an eye for an eye, a tooth for a tooth, an ear for an ear, and a life for a life. Since the principle of individual responsibility did not exist in ancient societies, someone else (such as his closest relative) could be punished instead of the criminal. Most time, it was ignored whether the act was a deliberate act, a life or blood cost was charged for each life.

The basis of this practice was that a member of the tribe to which the murderer belonged was handed over to the victim's family for execution, equivalent to the social status of the murdered person. The condition of social equivalence meant the execution of a member of the murderer's tribe who was equivalent to the murdered, in that the murdered person was male or female, slave or free, elite or commoner. For example, only one slave could be killed for a slave, and a woman for a woman. On this pre-Islamic understanding added a debate about whether a Muslim can be executed for a non-Muslim during the Islamic period.

The main verse for implementation in Islam is Al Baqara; 178 verse; : 'Believers! Retaliation is ordained for you regarding the people who were killed. Free versus free, captive versus captive, woman versus woman. Whoever is forgiven by the brother of the slain for a price, let him abide by the custom and pay the price well."

Qisas is available to the victim or victim's heirs against a convicted perpetrator of murder or intentional bodily injury. In the case of murder, qisas gives the right to take the life of the killer, if the latter is convicted and the court approves. Those who are entitled to qisas have the option of receiving monetary compensation (diyya) or granting pardon to the perpetrator instead.

Qisas and diyya are two of several forms of punishment in classical/traditional Islamic criminal jurisprudence, the others being Hudud and Ta'zir. The legal systems of Iran, Pakistan, Saudi Arabia, United Arab Emirates, Qatar and some Nigerian states currently provide for qisas.