Service substitution techniques are described. In an implementation, a substitution table is derived that specifies one or more service substitutions to be performed for content and that specifies particular geographic locations to perform at least one service substitution. One or more communications are formed to be streamed over a packet-switched network to a client that is to perform the at least one service substitution. The one or more communications include the substitution table and the content that corresponds to the at least one service substitution.