Maturity models in the domain of IOS have been developed and used for organizational design and analysis. Nevertheless, they typically provide a heterogeneous and inconsistent picture of relevant problem spaces (e.g. Supply Chain Management, interoperability problems, etc.). This effect is aggravated by the lack of a thorough model or method for self-appraisal with respect to an organization’s capabilities on technical, organizational and institutional levels to implement interorganizational processes. Our research attempts to fill this gap by constructing a maturity model for interorganizational integration that addresses the shortcomings of previous approaches. We analysed 23 maturity models in the domain of IOS to identify critical design elements for our own design process. We selected the model of Fraser et al. (2002) as our starting configuration that includes levels, characteristics, dimensions, elements and activities. From the analysis of alternative models we identified four additional design elements that we incorporated, namely class of entity, benefit, barrier and product. These extend the previously defined elements by Fraser et al. (2002).