In this paper I will focus on the morpho-syntactic differences between Standard Arabic and Tunisian Arabic. In the first part I will discuss the historical background and grammar of SA and TA then I will move to discuss the morpho-syntax of number, gender, case assignment, adjectives, and definiteness in both SA and TA. I will present some prior studies that discuss how the first language influences the second language (interference) on the syntactic and the morphological levels. In the second part, I will do an experiment on Tunisian native speakers to test the influence of Tunisian Arabic on the learning of Standard Arabic as a second language. The experiment will test whether Tunisian native speakers are aware of the differences between Tunisian and Standard Arabic and whether they can notice and state these differences or not. In the last part I will discuss the findings and draw a conclusion on the basis of them.