One key misconception about inheritance in OOP is that it is always the best solution for code reuse, when in fact, composition and interfaces can sometimes be more suitable. Another misconception is that multiple inheritance necessarily leads to a 'diamond problem' or ambiguity, but some languages, like Python, resolve this with well-defined rules. Some developers believe that all inherited classes should have overriding methods, whereas inheritance can be useful for providing default functionality without overriding. Finally, some assume that inheritance implies a strong coupling or interdependency among classes, while properly designed inheritance can maintain loose coupling and promote modularity.