Councillors decided on Thursday to change the designation of the Cox Green school to 'day special school' and turn part of the respite unit into a classroom.
Part of the site will remain available for 'respite care' however, offering temporary live in facilities for a limited number of pupils.
The old 'special need' school Holyport Manor had 138 on roll when it closed, moving into Manor Green School in Elizabeth Hawkes Way, Maidenhead.
Since then numbers have expanded to 173 and a further 20 children are joining in September.
No children live at the school at the moment and 65 per cent live of pupils come from within the Royal Borough - the rest being from neighbouring authorities.
Councillors have made it clear they want the school to remain a small, 'homely' place used mainly by Windsor and Maidenhead's residents - rather than a residential school attracting youngsters from far afield. The school will continue to provide education for two to 19-year-olds.
Manor Green has plans to develop its expertise in relation to autism, as 80 children in primary schools across the borough are identified as having the condition.
Top Ten Articles
The Met Office has issued a yellow alert for Windsor and Maidenhead, Slough and Wokingham, warning that rain moving eastwards across the south of the country may turn to snow in some places.