Tension in Public Procurement - The usage of a strategy tool: Public procurement is about public purchases, but also about sale of goods and services to the public sector. In research, public procurement is usually analyzed from a market or a transactional perspective. In contrast, this study uses a strategy-as-practice lens that focuses on the micro activities when public procurement is used as a strategy tool. Both buyers and sellers use public procurement, why public procurement as a strategy tool has potential to assist in their shared strategy work. However, if and how buyers and sellers participate in each other’s strategy work when using public procurement is unclear. The purpose of this thesis is to explore public procurement as a strategy tool and its use when buyers and sellers construct strategies. This is done by focusing on strategic work when buyers and sellers participate in public procurement. A qualitative and case-orientated approach were used to generate the empirical material, which included interviews, shadowing and documents. This study shows how public procurement as a strategy tool helps its users in their strategy work. When the tool was used, its content and the characteristics of the actor, but also practice, guided the strategy work. Three different hierarchal levels of practice were identified, why the ability to guide was determined by the level of detail and the scope of the practice. When constructing strategies, public procurement as a strategy tool emphasized managing information and strategy production. As a result, collecting information, identifying and sorting factors, were the core activities of strategic work. Strategy production was about managing positions and strategic factors. Three categories of factors were identified. Buyers and sellers did participate in each other's activities when constructing strategies, if they were given the opportunity and if they had something to gain from it. The parties' motives and characteristics, but also their perceived relational closeness, determined the design of the interaction and work. For practitioners, the use of public procurement as a strategy tool can contribute to align and make strategic work visible in relation to what is of strategic value.