A host of design approaches have been developed to support involving children in the design of new technologies. Unique approaches tend to be developed to involve new “audiences” of children – of different ages, with different abilities, at different levels of involvement – in the design process. While goals of design approaches tend to be explicitly discussed, there are common themes and repeated patterns which appear in multiple design approaches. This monograph identifies these recurrent themes and patterns within design approaches for working with children as informants, design partners or software designers. These themes and patterns have been sorted into groups of: principles or heuristics, which act as guidelines to designers working with children; decision points where designers working with children will need to make choices; common activity patterns and communication patterns which appear frequently in design approaches for working with children, but are often under-described; and emergent phenomena which design approaches may attempt to invoke. These themes and patterns have been identified through comparison of methods and techniques for designing with children, young children, and children with a communication gap caused by disability or cross-cultural work. This catalogue of themes and patterns will be of use for designers working with children in participatory design and co-design activities. Awareness of these factors will allow designers selecting existing design approaches, or creating their own, to better understand and compare existing design approaches.