O and H always make covalent bond. You can tell because they are both non metals. Two nonmetals always make a covalent bond.(If you see two non metals together, you know that they can make a polar covalent or non polar covalent bond, but never ionic). Only when metal combine with nonmetal, do they make a ionic bond. One other thing, Oxygen is very electronegative atom (this means that it likes electrons a lot and attracts them toward itself more strongly them most other atoms) therefore it tends to form polar covalent bonds. Polar covalent bond is a kind of covalent bond where electrons are sheared unevenly. So the most complete answer to your question is: oxygen and hydrogen make a polar covalent bond. Solution O and H always make covalent bond. You can tell because they are both non metals. Two nonmetals always make a covalent bond.(If you see two non metals together, you know that they can make a polar covalent or non polar covalent bond, but never ionic). Only when metal combine with nonmetal, do they make a ionic bond. One other thing, Oxygen is very electronegative atom (this means that it likes electrons a lot and attracts them toward itself more strongly them most other atoms) therefore it tends to form polar covalent bonds. Polar covalent bond is a kind of covalent bond where electrons are sheared unevenly. So the most complete answer to your question is: oxygen and hydrogen make a polar covalent bond..