In a step forward for equality, the change will prevent conservative bishops from blocking women from such roles.
But the decree from the Vatican on Monday noted that these roles were fundamentally different from allowing women to be ordained as priests, something that will still not be allowed.
The Vatican stressed that these lay roles, officially known as lector and acolyte, were “essentially distinct” from the ordained ministry of the priesthood.
Reporting on the decree, the official Vatican News website said that women had been performing some of these duties for years under the authorisation of local bishops, but had lacked, until now, a full papal mandate.
The site quoted Francis as writing in a letter setting out his decision that “within the spectrum of renewal traced out by the Second Vatican Council, the urgency is being ever more felt today to rediscover the co-responsibility of all of the baptised in the church, and the mission of the laity in a particular way”.
Francis said many bishops from around the world had said that the change to the Code of Canon Law was necessary to respond to the “needs of the times”.
The pontiff has been under pressure to allow women to be deacons – ordained ministers who perform many of the same functions as priests, such as presiding over weddings, baptisms and funerals. Currently, the ministry is reserved for men.
The Pope has created a second commission of experts to study whether women could be deacons, after the first one failed to reach a consensus.
Advocates for expanding the diaconate to include women say doing so would give women greater say in the ministry and governance of the church, while also helping address priest shortages in several parts of the world.
Opponents say allowing it would become a slippery slope towards ordaining women to the priesthood.
Additional reporting by agencies