The bill was passed by the state House of Representatives by 56 votes to 15, having been passed last week by the Senate by 26 votes to 12. The state Governor signed the bill into law immediately.
Same-sex marriages will be available in Rhode Island from 1st August.
Rhode Island is the 10th US state to introduce equal marriage, and the last of the six New England states to do so. The District of Columbia and three tribal jurisdictions also provide equal marriage in the US.
In the past four weeks, four parliaments, on four different continents, have passed bills introducing equal marriage, in Uruguay, New Zealand, France and Rhode Island.
There are also equal marriage bills currently progressing in a number of other parliaments, including Luxembourg, and, in the US, Delaware, Illinois and Minnesota.
And of course the UK Parliament is considering the Marriage (Same Sex Couples) Bill for England & Wales. That bill is expected to have two more days of debate in the House of Commons towards the end of this month, and will then move to the House of Lords.
We are currently hoping to see the Marriage and Civil Partnership (Scotland) Bill introduced in the Scottish Parliament in the early summer.