Gestures such as finger counting, pointing, and touching have been found to facilitate mathematical development in preschool and school-aged children. However, little is known about the types of mathematically related gestures used by parent-toddler dyads to facilitate early mathematics learning during the first 3 years of life. A total of 24 children (12 boys and 12 girls) between 18 and 25 months of age and their parents participated in a recorded 30-minute play session at home. After the play session, each child completed a task to ascertain his or her counting ability from one to five. Parents initiated significantly more instances of mathematically related gestures than did the children. In contrast, children responded with more gestures to mathematically related talk than did their parents. The most frequent types of gestures produced are collecting/grouping of items in an array, counting objects while enumerating, tapping/touching, holding up, and pointing at an item. A total of 13 children demonstrated some understanding of the five counting principles except the cardinality principle proposed by Gelman and Gallistel. Our findings suggest that parents use specific types of mathematically related gestures during play with their toddlers. (author abstract)