Software testing groups are playing an increasingly prominent role in both the software development lifecycle (SDLC) and in the long-term planning of technology architectures that support large-scale organizational information systems. The advent of integrated enterprise architectures (EA) provides new opportunities for testing groups to play a proactive role in building consistent and testable guidelines for improving enterprise-wide software quality. Given that testing groups historically have not been invited to participate in EA decisions, there is little academic literature or industry best practices on approaches that testers might use to guide their participation. This article draws lessons from the experience of a Fortune 100 corporation whose testing group used theoretical notions of “testability” to guide its involvement in an EA acquisition process. It describes how it operationalized testability criteria, incorporating controllability, observability, and simplicity, into various stages of the process and illustrates the benefits and challenges of taking such an approach.