Staff will be marking the occasion on Wednesday with a series of activities throughout the day and an exhibition of past photographs, and books and films of the time.
A free birthday party will take place from 2pm to 4pm, for members of the public to drop in and enjoy some birthday cake and refreshments.
There will also be The Very Hungry Code-a-Pillar Storytime at 3.30pm, to join in birthday celebrations for The Very Hungry Caterpillar which is also 50 this year.
Storytime tickets, which includes meeting the Code-a-Pillar, are free but guests must reserve a place.
From humble beginnings lending books from the Town Hall in the 1920s, Shoreham Library has come a long way since the branch officially opened on June 12, 1969.
The branch was officially opened by Clifford Musgrave OBE as the first instalment of a group of county council buildings, each with its own special features.
Clifford praised the virtues of the ‘new ultra-modern building, fine architecture and modern methods of computerisation’ and congratulated the people of Shoreham on acquiring such a magnificent library.
He also commented on the collection of books on Shoreham’s history, a town that had been immortalised in literature and art.
Shoreham Library houses more than 20,000 items of stock and was visited more than 100,000 times in a single year. There are seven staff members plus the cluster manager, many of whom have years of experience and know the majority of customers by name.
They are also supported by a small team of volunteers who help with computer queries, children’s activities and taking books to housebound readers in the community.
The library hosts several activities for adults and children, with weekly rhyme time sessions so popular they now have to run two sessions.