The last two decades have witnessed a stark increase of initiatives using sport in the international development sector, building on the perceived potential of sport to trigger positive social change, forming a sector widely known as the Sport for Development (SfD) sector. Critical voices (mainly academic) have pointed to the lack of evidence backing these claims. This led funders and policymakers to require SfD organisations to evaluate their programmes through collecting quantitative data using a pre-defined set of international indicators in a quest for cross-sectorial comparison. This paper relies on 14 months of fieldwork within an SfD organisation during which an organisational, multi-sited, and multimodal ethnographic approach was used. Being involved in the programme evaluation allowed for a detailed examination of the practices of monitoring and evaluation that underpin the production of knowledge about SfD through programme evaluation. Ethnographic data co-produced with a variety of SfD practitioners show the many tensions that underpin the production of knowledge within SfD organisations. Discourses around the intrinsic potential of sport for positive social change complement discourses about the need for organisations to produce indisputable quantitative and comparable evidence of the effectiveness of sport to succeed where international development initiatives have failed. However, in contradiction with this quest for comparability, SfD practitioners align their practices of knowledge production with their own interests by performing microtechniques of interpretation. These findings show the tensions and complex processes that underpin the production of knowledge about the use of sport in international development contexts: tensions between the nearly consensual discourses about sport, the epistemic rigidity to produce cross-cultural, seemingly indisputable evidence, and the variety of individual and collective interests that can be found in small SfD programme. This landscape makes SfD an ideal terrain to explore and theorise knowledge production from an anthropological perspective.