Front-end architecture having split triplexers for carrier aggregation and MIMO support. In some embodiments, a multiplexing architecture can include an assembly of filters configured to support carrier aggregation with one or more antennas. The assembly of filters can include a first triplexer configured to support a low-band, a mid-band, and a first high-band. The assembly of filters can further include a second triplexer configured to support the low-band, the mid-band, and a second high-band. The multiplexing architecture can further include a switch assembly implemented between the assembly of filters and respective one or more nodes associated with the one or more antennas.