We consider f (R) gravity theories in the presence of a scalar field minimally coupled to gravity with a self-interacting potential in (2 + 1)-dimensions. Without specifying the form of the f (R) function, we first obtain an exact black hole solution dressed with scalar hair with the scalar charge to appear in the f (R) function and we discuss its thermodynamics. This solution at large distances gives a hairy BTZ black hole, and it reduces to the BTZ black hole when the scalar field decouples. In a pure f (R) gravity supported by the scalar field, we find an exact hairy black hole similar to the BTZ black hole with phantom hair and an analytic f (R) form and discuss its thermodynamics. CONTENTS I. Introduction 1 II. The setup-derivation of the field equations 2 A. Without self-interacting potential 3 B. With self-interacting potential 3 III. Black hole solutions 4 A. c 1 = 1, c 2 = 0 4 B. Exact Black Hole Solution with Phantom Hair 9 IV. Conclusions 12 Acknowledgments 12 References 12