RIYADH, Saudi Arabia — Saudi King Abdullah announced Sunday that the nation’s women will gain the right to vote and run as candidates in local elections to be held in 2015 in a major advancement for the rights of women in the deeply conservative Muslim kingdom.

In an annual speech before his advisory assembly, or Shura Council, the Saudi monarch said he ordered the step after consulting with the nation’s top religious clerics, whose advice carries great weight in the kingdom.

“We refuse to marginalize the role of women in Saudi society and in every aspect, within the rules of Sharia,” Abdullah said, referring to the Islamic law that governs many aspects of Saudi life.

The right to vote is by far the biggest change introduced by Abdullah, considered a reformer, who formally ascended to the throne in 2005.

Abdullah said the changes announced Sunday would also allow women to be appointed to the Shura Council, the advisory body selected by the king that is currently all-male.