The Children's Rights Alliance is calling for the Government to recognise that child homelessness is a national emergency.
Publishing its annual 'Report Card', the organisation said more public housing must be provided to tackle the crisis, rather than over-relying on the private sector.
Nearly 4,000 children were living in emergency accommodation in November 2018, most of them in Dublin.
Chief executive Tanya Ward said "family hubs and other interim solutions only provided a sticking plaster" to what was a complex problem.
She said mental health was also a concern, with 7,206 children on waiting lists for appointments with community and psychology support services. She said there were a further 2,250 children waiting for specialist treatments.
Overall, the Report Card awarded the Government a grade of C for living up to its promises to children.
That's up slightly on the C- they were given last year, and it's a significant improvement on the D+ the Government was awarded in 2017.
Ms Ward said important steps had been taken last year to "protect and empower" children. She said Ireland was the first country in the world, for example, to introduce an LGBTI+ strategy.
Judge Catherine McGuinness, who chaired the panel which graded the Government, said she was concerned about the increasing number of homeless Traveller families - and the discrimination Travellers continue to face in accessing services and housing.
The number of Travellers living in temporary accommodation increased from 3,560 in 2011 to 3,718 in 2016. 40% of Traveller families live in overcrowded accommodation, compared to 6% of the general population.