This chapter presents finite blocklength analyses for mismatched multiterminal transmission, including multiple access channel (MAC), random access channel (RAC), and broadcast channel (BC). MAC and RAC are models for uplink multiuser communication, while BC models downlink multiuser communication. Mismatched codes are proposed using the P2P case and the idea of either successive interference cancellation (SIC) or joint decoding (JD). The low-latency performance of all three problems is presented. One take-home message exists for each problem: for MAC, JD has better low-latency performance than SIC; for RAC, JD has better performance regardless of latency; for BC, both JD and SIC achieve the same low-latency performance. The readers can learn coding schemes for various models of multiuser data transmission and their low-latency theoretical performance.