We introduce a simulator for a quantum internet with the specific goal to support software development. A quantum internet consists of local quantum processors, which are interconnected by quantum communication channels that enable the transmission of qubits between the different processors. While many simulators exist for local quantum processors, there is presently no simulator for a quantum internet tailored towards software development. Quantum internet protocols require both classical as well as quantum information to be exchanged between the network nodes, next to the execution of gates and measurements on a local quantum processor. This requires quantum internet software to integrate classical communication programming practises with novel quantum ones. SimulaQron is built to enable application development and explore software engineering practises for a quantum internet. SimulaQron can be run on one or more classical computers to simulate local quantum processors, which are transparently connected in the background to enable the transmission of qubits or the generation of entanglement between remote processors. Application software can access the simulated local quantum processors to execute local quantum instructions and measurements, but also to transmit qubits to remote nodes in the network. SimulaQron features a modular design that performs a distributed simulation based on any existing simulation of a quantum computer capable of integrating with Python. Programming libraries for Python and C are provided to facilitate application development.