Twelve professionally maintained Har Tru tennis courts and the excellent availability of court time make tennis a favorite activity at Dellwood. In fact, Dellwood Country Club is the official home of the Rockland County Tennis Association's Championships and is host to many charity tournaments.

Certified USPTA professional instructors offer private and group lessons and tennis clinics to members. Men's and ladies' individual and mixed tournaments and intra- and inter-club leagues are conducted throughout the season. A full tennis membership at Dellwood also includes limited golf privileges. Youngsters between the ages of four and eighteen can take advantage of the Junior Development Program. This program runs from May to September and allows young people to develop their tennis skills through a series of workshops, clinics and tournaments.

Dellwood's Tennis Pro Shop, open six days a week, is stocked with the latest racquet models, name-brand apparel and demo racquets. Re-stringing services are available to members.