As part of the five-year deal, Maxol will provide petroleum fuels to 13 service stations owned by the Henderson Group and these will be now branded with Maxol's blue and yellow forecourt image.
Brian Donaldson, general manager retail and marketing at Maxol Group, said: "Both Maxol and the Henderson Group are locally owned, family-run businesses, which despite the economic downturn have continued to invest, and both are committed to the highest standards of customer care.
"Spar has an established reputation for value and an extensive portfolio of convenience products which means we can expand the range of products we provide."
Henderson Wholesale sales and marketing director Patrick Doody added: "This deal allows us to expand our portfolio of Spar stores throughout the Province. The combination of two strong brands will result in first-class convenience stores and petrol forecourts."