Abstract The main aim of this paper is to test Matrix Language Frame (MLF) model of code-switching with Persian–English data, and to see whether the data confirm the principles of the model or not. A Persian–English corpus was provided from the formal and informal conversations of Persian–English bilinguals on TV shows. Then the three principles of the MLF model, that is, the Matrix Language principle, asymmetry principle, and uniform structure principle were verified. The results of the analyses suggest general support for the four principles of the MLF model. It is also concluded that Persian–English codeswitching does seem to be a ‘classic’ case of code-switching.