The chapel has been enlarged to a 550-person capacity with an additional mezzanine installed.
St Hilda’s director of development Amanda Burke said the school was thrilled both significant projects had now been completed.
The buildings had been envisioned as spiritual and social hubs to meet the needs of pupils and the school community, she said.
The school received grant funding from the Community Facilities Fund and Otago Community Trust, along with several fundraising events such as a fashion show, art auction and Blue Ribbon installation.
The total cost of the redevelopment was nearly $7 million.