This paper represents an initial exploration of researcher-informant relationships which develop when naturalistic researchers spend long periods of time watching and recording the details of classroom activity for which a teacher has basic responsibility. The goals of this paper are to present a discussion of the significance of researcher-teacher relationships in naturalistic classroom studies; to discuss observations drawn from several classroom studies conducted by the authors; and to describe a continuum of researcher-teacher relationships. The continuum ranges from antagonistic-defensive relationships, through reluctant-protective and accommodating-cooperative relationships, to participating-collaborative relationships. Several implications designed to assist researchers are drawn: (1) decisions regarding researcher-teacher relationships should be made as part of the project design and should be based on research objectives; (2) the desired researcher-teacher relationship and a plan for maintaining it should be made explicit; and (3) researcher-teacher relationships should be actively monitored as studies are implemented. (BW)