The Larne school held an event on September 30 to recognise the important milestone, with pupils also marking the occasion by burying a time capsule filled with messages in the school garden.
We’ve had a look through the archives and turned up these fab photos of events at the school through the years.
Can you spot any familiar faces?
21. Through the years
Members of the St MacNissi's Primary School ECO Committee pictured during a visit to the Larne Mayor's Parlour in recognition of their school receiving the Eco Schools Green Flag, 2013. With them are teacher Mrs Higgins, Principal Mrs Brady, Mayor Maureen Morrow and LBC Environmental Education Officer Barry Tapster. INLT 26-347-PR Photo: Peter Rippon
22. Through the years
St MacNissi's Primary School Principal, Mrs Brady and Speech and Drama teacher Mrs Linzi Conway with pupils from the school who were awarded London Academy of Music Drama and Arts (LAMDA) certificates in 2012. INLT 23-302-PR Photo: Peter Rippon