RTÉ2 (formerly branded as RTÉ 2 from 1978–88, Network 2 from 1988–97, N2 from 1997–2004 and RTÉ Two from 2004–14) is an Irish free-to-air television channel operated by public service broadcaster RTÉ. It was launched on 2 November 1978 as the Republic of Ireland's second television channel, at which point the pre-existing channel was renamed RTÉ 1 (currently RTÉ One). The channel airs content aimed at 16-45 year-olds.

In the 1970s, the Irish government considered three options for the introduction of a second television service: the re-transmission of BBC1 Northern Ireland; authorization of an independent commercial service; or charging RTÉ with the establishment of a second national channel. It was the last of these that was finally chosen.

After a period of test transmissions in the late summer and autumn the channel began scheduled broadcasting at 20:00 on 2 November 1978, opening with a broadcast of a gala ceremony from Cork Opera House. Owing to a technical error, audio from BBC2 was played during the countdown instead of the proper soundtrack. When the channel commenced programmes, there was no audio for the initial 15 seconds.

The opening night's line up was as follows:

Up to 60% of the Republic of Ireland could receive UK channels via spillover or via cable. Cable in the republic was only permitted in areas of spillover up to the mid-1980s, to provide viewers with better reception of channels they could already receive over the air. Hence RTÉ 2 was aimed at those that did not have the UK channels. To this end one of their main remits was the re-broadcasting of UK programming to Irish audiences, that would not otherwise be seen on RTÉ 1.

The official opening on RTE 2 outlined the promised content of the new channel, with presenter Róisín Harkin stating: "from ten to seven [i.e. 6:50 p.m.] each weekday, three o'clock on Saturdays and six o'clock on Sundays, RTÉ 2 will be bringing you the best of BBC, ITV and other first rate programming." In the first two years of the channel, it would normally open at 6pm and close down for the night at 11.30pm.

British soap drama Coronation Street aired on the channel simultaneously with ITV's broadcasts of the programme (this continued until 1992 when it was put on RTÉ 1 due to the Olympic Games coverage). It broadcast much live programming from the BBC and ITV including Top of the Pops. However, the channel in its initial format was not considered a success. It was on air from 18:00 until 23:30 during the week, with an earlier start around 15:30 at weekends.

However, by 1987, RTÉ 2 rebranded as part of RTÉ's 25th celebrations relaunched with a new corporate logo and TV idents, this would be the first time that the RTÉ corporate logo would be seen on RTÉ2. While the rebrand was a small success for the channel it was felt that RTÉ 2 and RTÉ 1 needed more specific audiences. RTÉ 2 at this stage was becoming more and more associated with youth orientated programming and sports programming (especially as UK and other international channels were becoming more and more available across the country). In 1988, the majority of sporting and children's programming was moved to Network 2, the new name for RTÉ 2.