Daniella Timperley from Randalstown is one of 600 people across the UK to be selected.
It is in recognition of her contribution to her local community.
The 18-year-old will see Prince Harry wed his American actress fiancee Meghan Markle in St George's Chapel at Windsor Castle on May 19 and also attend a lunchtime reception at St George's Hall given by the Queen.
The 'public' invitations were reported to have been posted last week.
The news was announced by Daniella's school, St Louis Grammar in Ballymena, on its Twitter feed this week in a post also referencing an all-Ireland youth volunteer of the year accolade she won at the Pramerica Spirit of Community Awards.
It said: "What a week it has been for Daniella! Not only was she named Top Youth Volunteer 2018, she has also received an invitation to the royal wedding of Prince Harry & Meghan Markle as a result of her extensive charity work!"
Daniella has an impressive CV of volunteer work, including involvement with Women's Aid, which she represented on the BBC Children in Need Youth Panel in 2015, helping to co-ordinate fundraising efforts and voicing the needs of those helped by the organisation.
She has also volunteered in care homes, completed intergenerational projects with the elderly, helped at a homework club in Ballymena with younger children and at the Antrim summer scheme, where she completed OCN accreditations in mental health, domestic violence, understanding risks and self-esteem.
This spring looks like being a busy one for the sixth former, who as well as travelling to London in May, will next month travel on an all-expenses paid trip to Washington DC to meet with youth volunteers from across America and participate in the Prudential Spirit of Community Awards ceremony.
An estimated 100,000 people are expected to visit Windsor in May for the wedding, amid a security operation described yesterday as "among the largest in Thames Valley Police's history".
Millions of viewers across the world are expected to tune in to watch the television coverage of the royal nuptials.