What causes cramps in my toes?

Muscle fatigue : Muscles cramp when they fatigued. This often happens when your feet are not properly supported, causing them to be overworked. Switching to properly supportive shoe gear should help. If not, see a podiatrist to discuss custom biomechanical orthotics. Also, stay well-hydrated and consider electrolyte replacement if you are exercising.

Cramps : Many things can cause cramps in foot. Low potassium is one but most common is due to a neuroma or nerve lesion. See podiatrist.