Anyone who might otherwise find themselves spending the day alone is invited to attend the event at the Sir Robert Woodard Academy in Boundstone Lane.
Chef Cheryl Bailey, catering manager at the school, and a team of volunteers will help cook a full Christmas lunch with all the trimmings.
The event will start at 11.30am with hot chocolate and mince pies, before a Christmas sing-a-long and the meal.
Volunteers can help offer transport to bring guests to the venue and return them home at the end of the day when the event finishes at 3.30pm.
Organiser Janice Roberts said: “Our Christmas day is for anyone who is spending this special day on their own and would like some company, a single parent and child, there is no age limit!”
She asked for residents to spread word of the event among their neighbours.
The lunch will cater for up to 70 guests.
Tickets are available to collect at The Sompting Big Local Shop in Cokeham Road, Sompting, and at Lancing Parish Hall in South Street, Lancing.
Donations of gifts and food have kindly been given by residents and local companies, including Harris and Hoole and Lloyds bank.
Organisers event are also holding a free Christmas Day lunch in Shoreham for the second year running.
It will be the first time the event has been held in Lancing.