Joe O'Brien is an Irish Green Party politician who has served as a Minister of State since July 2020. He has been a Teachta Dála (TD) for the Dublin Fingal constituency since 2019.

The Green Party is a green political party that operates in the Republic of Ireland and Northern Ireland. It holds a pro-European stance. It was founded as the Ecology Party of Ireland in 1981 by Dublin teacher Christopher Fettes. The party became the Green Alliance in 1983 and adopted its current English language name in 1987 while the Irish name was kept unchanged. The party leader is Eamon Ryan, and the deputy leader is Catherine Martin and the cathaoirleach (chairperson) is Pauline O'Reilly. Green Party candidates have been elected to most levels of representation: local government, Dáil Éireann, the Northern Ireland Assembly, and the European Parliament.