COTS (commercial off-the-shelf) component designers and developers often envision different usage contexts for their component and, therefore, provide it with adaptation possibilities. These adaptation possibilities are especially important when considering system families. System family engineering is currently an emerging discipline. Variability is a core property of system families which allows deriving different customer-specific applications from a core artifact base. A system family’s core artifact base may also be populated with COTS components. These COTS components then need to support the system family’s variability, i.e. they have to offer the possibility to adapt them to different customer-specific applications. Through their adaptation possibilities COTS components are able to meet this requirement. During COTS evaluation, a system family’s requirements and architecture need to be taken into account. Variability is inherent in both. That is, the question is how to evaluate COTS with regard to variable features. In this paper, we describe variability in architecture in more detail and point out how this variability needs to be reflected in COTS evaluation criteria. The contribution is an extension of ‘traditional’ COTS evaluation criteria in order to consider a system family’s variability.