In Sierra Leone, abortion is a criminal offence. Its abortion law does not specify any grounds for legal abortion. It is unclear whether abortion is permitted to save the life of the mother, as a British judicial decision allowing such abortions is untested in Sierra Leone. Abortion is covered in the country's medical code of ethics, but there is no government training for providers. Prosecution of abortion is uncommon.

Abortion is illegal under an 1861 British law, though the British colonial government never officially codified an abortion law. In the 2010s and 2020s, activists, politicians, and international organizations supported proposals to legalise abortion. Religious groups have supported the ban. Sierra Leone ratified the Maputo Protocol in 2015. A bill allowing abortion, first raised in 2010, was approved by Parliament after being introduced by Isata Kabia in 2015. The bill failed as President Ernest Bai Koroma refused to sign it. This law was heavily debated despite a stigma against the subject. In 2022, the government of Julius Maada Bio backed a new reproductive health bill that would lift the abortion ban.

Unsafe abortions are a major factor in Sierra Leone's maternal mortality rate, one of the highest in the world. Post-abortion care is available, primarily using the dilation and curettage method. The country has a stigma surrounding abortion, and many girls have little knowledge of it. Some rely on clandestine providers. Others acquire drugs for self-induced abortions without medical advice. Factors that motivate abortions include the inability to afford a baby, disapproval of the relationship by the family, and lack of contraceptives. Factors leading women not to have abortions include lack of knowledge and lack of access to providers.

The abortion ban in Sierra Leone has not been modified since the British colonial era. The Offences Against the Person Act 1861, an act of the British Parliament grouped with the Criminal Law Consolidation Acts 1861, criminalises acts performed to terminate a pregnancy. Sierra Leone is the only former British colony to still apply this act. The law does not specify any grounds for legal abortion. The British judicial decision Rex v Bourne on the same law's application found that it permits abortions to save the life of the mother. This has not been brought up in Sierra Leone's courts, so it is unclear whether such abortions are permitted.

Public-sector health providers do not have training or guidelines about providing abortions. Sierra Leone's medical code of ethics addresses abortion, and a WHO survey in 2021 found that the country's health benefit package included abortion. The National Protocols and Guidelines for Emergency Obstetric and Newborn Care (2018) sanction post-abortion care using misoprostol. Private organizations have legally imported abortion drugs, but distribution is legally limited.

Due to the stigma, abortion cases are resolved within families, and are only pursued in court if they result in death, according to AdvocAid. Nurses have been charged with manslaughter for aiding in abortions that resulted in death. In January 2011, a pregnant woman with heavy bleeding was detained for allegedly having an abortion and was released after proof that she was still pregnant.

During the British colonial era, Sierra Leone lacked an official abortion law and was subject to English common law. The Offences Against the Person Act 1861, an act of the British Parliament grouped with the Criminal Law Consolidation Acts 1861, criminalises acts performed to terminate a pregnancy. This law was in effect in Sierra Leone, while common law applied to an unclear extent. It is unclear whether Sierra Leone applied a common law principle that permitted abortions before the quickening of the pregnancy. It is also unclear whether Sierra Leone applied the decision of Rex v Bourne, permitting life-saving abortions.

In July 2015, Sierra Leone became a party to the Maputo Protocol, which includes provisions about abortion. Members of parliament heavily debated the ratification. Opponents said that the protocol was an example of Western imperialist morality and that a policy against abortion defended Sierra Leone's cultural sovereignty.