In actor-oriented design, programmers make hierarchical compositions of concurrent components. As embedded systems become increasingly complex, these compositions become correspondingly complex in the number of actors, the depth of hierarchies, and the connections between ports. We propose higher-order composition languages as a way to specify these actor-oriented models. The key to these languages is the ability to succinctly specify configurations with higher-order parameters---parameters that themselves might be configurations. We present a formalism which allows us to describe arbitrarily complex configurations of components with higher-order parameters. This formalism is an extension of the standard lambda calculus.