A wheelchair has a wheelchair frame resting on wheels and supporting a seat,and a backrestframe supporting a backrest. The backrest frame is pivotally connected to thewheelchair frameand has two lateral tubular elements, each tubular element having an upper endportion providedwith a handle and a lower end portion pivotally mounted on an axis supportedon a supportfixedly connected to the wheelchair frame. Locking/unlocking means areprovided forpreventing the lower end portion of at least one of the tubular elements, andpreferably of eachone of the tubular elements, to pivot relative to the corresponding support ina locked inclinedposition of the backrest frame. The locking/unlocking means configured topermit a steplessadjustment of the angle between a plane defined by the backrest and a planedefined by the seatin the locked inclined position.
