The Lords Spiritual (Women) Act 2015 (c. 18) is an act of Parliament of the United Kingdom. It states that whenever a vacancy arises among the Lords Spiritual during the next ten years after the act comes into force, the position has to be filled by a woman, if there is one who is eligible. In this case, the act supersedes section 5 of the Bishoprics Act 1878, which would otherwise require "the issue of a writ of summons to that bishop of a see in England who having been longest bishop of a see in England has not previously become entitled to such writ".^[1] It does not apply to the five sees of Canterbury, York, London, Durham or Winchester, which are always represented in the House of Lords.

The act was passed half a year after the Bishops and Priests (Consecration and Ordination of Women) Measure 2014 authorised the Church of England to appoint women as bishops.^[2]

The first female diocesan bishop, and thus the first female Lord Spiritual due to this act, was Rachel Treweek in 2015.^[3] Consecrated Bishop of Gloucester on 22 July 2015^[4] and enthroned on 19 September 2015,^[5] she joined the Lords on 7 September 2015 with the full title The Rt Rev. the Lord Bishop of Gloucester,^[6] and was introduced to the House by the Archbishop of Canterbury and the Bishop of London on 26 October 2015.^[7] She made her maiden speech on 7 March 2016.^[8]

Since then, Christine Hardman (2016), Viv Faull (2018), Libby Lane (2019), Guli Francis-Dehqani (2021), and Helen-Ann Hartley (2023) have also entered the Lords due to this Act shortly after becoming diocesan bishops. Therefore 6 out of 20 vacant Lords positions occurring in the first nine years of the Act (as of February 2024) have been filled by women.^{[lower-alpha 1]} Without the Act, Treweek and Hardman would only have become Lords Spiritual in late 2021.^{[lower-alpha 2]}

In addition (and independently of the Act), Sarah Mullally entered the Lords ex officio when appointed Bishop of London in 2018.

• List of bishops in the Church of England, which lists the current Lords Spiritual and the seniority of service of the other diocesan bishops
• Women in the House of Lords