In a judgment handed down on Friday, the court found that it was unfair to exclude members of the church from the full and equal enjoyment of all rights and freedoms that the church offers.
These included the opportunity to get married in the church.
In 2015, the church decided to allow individual church councils to recognise same-sex marriages, and scrapped a rule that gay ministers of the church had to be celibate.
A year later, in 2016, the church adopted a new policy, scrapping the 2015 decision.
Reverend Laurie Gaum, his father Dr Frits Gaum and eight other members of the Dutch Reformed Church launched the High Court application to have the 2016 decision set aside and declared unconstitutional. DM