Cucumber (Cucumis sativus L.) and Cucurbita species (squashes, pumpkins, and gourds), belonging to the Cucurbitaceae family, are among the major vegetable crops in the world. Transgenic approaches could contribute to the accumulation of new knowledge of these species and to the development of elite cultivars. Despite this, research reports using transformants of these species are very limited so far. One of the reasons for this may be that although there are effective transformation methods, these methods are not well known among researchers. In the present review, we describe efficient protocols for the transformation of cucumber and squash plants and mention possible pitfalls in and advice for following these protocols. In addition, we discuss the current progress of genetic transformation research using cucumbers and squash, including genome editing.