Systems and methods are disclosed for least cost acquirer routing based on pricing models. One method comprises: receiving transaction-related information from a merchant, the transaction-related information including a payment network identifier of the payment network used in the initiated payment transaction; identifying the payment network used based on the payment network identifier determining the primary qualification criteria pertaining to the payment network used; determining an interchange rate and an interchange category based on the primary qualification criteria and the received transaction related information; determining a pricing model of an acquirer that yields the lowest fees applicable to the merchant based on one or more of, the transaction related information, the primary qualification criteria, and the interchange category; and transmitting the transaction-related information to the acquirer.