Described here are devices, systems, and methods for treating one or more conditions (such as dry eye) or improving ocular health by providing stimulation to nasal or sinus tissue. Generally, the devices may be handheld or implantable. In some variations, the handheld devices may have a stimulator body and a stimulator probe having one or more nasal insertion prongs. When the devices and systems are used to treat dry eye, nasal or sinus tissue may be stimulated to increase tear production, reduce the symptoms of dry eye, and/or improve ocular surface health.