Under debate is how 'outside' planners can best work with different cultures to ensure inclusion and participation. It is evident why in general planners need to expand their understanding of different cultures if they are to work with them effectively and appropriately, but not enough empirical research has been undertaken on what planners find they need to know in the specific context of working with First Nations. On the basis of a literature review and the author's own extensive experience with First Nations, seven areas of knowledge (themes) were identified as likely to be relevant to outside planners working with First Nations. These seven knowledge themes guided interviews with nine planners who were asked which of these kinds of knowledge they found useful when working with First Nations in western and northern Canada, and Alaska, particularly when facilitating participatory planning. The first six identified themes concern knowledge of First Nations' value and traditional knowledge systems; authority relations; social organization; communication processes; participation processes; and capacity for planning. The seventh theme is knowledge about effective methods that planners can employ to facilitate participatory relationships with First Nations communities and individuals. The findings from the interviews add to our understanding of what outside planners need to consider when they work with First Nations. The findings are particularly instructive in the theme areas of First Nations' communication and participation processes, and in the area of planner practice. It was also found that while the seven areas of knowledge are relevant to planners at all stages of working with First Nations, they are particularly important when planners and First Nations begin their planning relationship, when planners first enter a community, and when planners are helping communities to develop their planning processes. Research is now needed on what First Nations' individuals themselves think planners should know if they are to be effective in promoting culturally appropriate, inclusive, and participatory planning in First Nations settings. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate