Devices, systems and methods wherein a dilator, such as a balloon or other expandable member, is positionable within the frontal sinus ostium and adjacent frontal recess and useable to dilate the frontal sinus ostium and substantially all of the frontal sinus recess without requiring repositioning and repeated re-expansion of the dilator. One balloon catheter device of the invention comprises a catheter body that is less than about 50 cm in length (and in some embodiments less than 25 cm in length and a semi-compliant or non-compliant balloon on the catheter body. The balloon may have a working length of about 12 mm to about 30 mm and a width at its widest point when fully inflated of about 2 mm to about 7 mm. Such balloon may be constructed to withstand inflation pressures of about 12 atmospheres. In some embodiments, the dilator is advanced through or over a guide (e.g., guidewire or guide catheter) that has a preformed shape.