We develop the rudiments of a theory of parametrized ∞-operads, including parametrized generalizations of monoidal envelopes, Day convolution, operadic left Kan extensions, results on limits and colimits of algebras, and the symmetric monoidal Yoneda embedding. * (pα) f ′ * (C U ′ ) ≃ (f * C) V ′ . Let (f * C) γ be the set of these diagrams.