Many industrial firms motivate structural changes by an increased focus on core activities and reduced ownership of non-core activities. However, classifying maintenance activities as either core or non-core can be difficult, since maintenance is a support function strongly linked to the production core within a manufacturing firm. Based on a multiple case study that included four buying firms and four suppliers within the process industry, this paper investigates how the relative capabilities of the firms affect the governance decision about maintenance outsourcing. A conceptual framework built on a distinction between core-close and core-distant maintenance and between different maintenance capabilities is presented. The subsequent empirical analysis illustrates how the developed framework can be used for both analyzing and guiding firms’ decisions about outsourcing and governance regarding maintenance.