Daniel P Malloy, the governor of the state, has signed the measure into law to ban licensed health care providers from conducting the dangerous practice on people under 18.
Senator Beth Bye called it a ‘dangerous practice that relies on shame’.
The measure had cross-party support, with Republican Senator Heather Somers saying conversion therapy is based on the ‘false assumption’ there’s something wrong with people are not heterosexual.
Connecticut joins California, New Jersey, New York, Oregon, Illinois, Vermont, Washington DC and New Mexico to ban ‘gay cure’ therapy for minors.
Malta is so far the only country in the world to protect LGBT teens from the abuse.
UK Prime Minister Theresa May rejected a call to make ‘gay cure’ therapy illegal earlier this year.
Earlier this month, the US Supreme Court refused to hear a minister’s challenge to California’s ban. Reverend Donald Welch, a minister and family therapist, claimed the law infringed his religious freedom.
VP Mike Pence has also supported conversion therapy.