This paper aims to identify EFL teachers’ perceptions of the cross-linguistic factors affecting the interlanguage system progress of Saudi learners of EFL at Najran University. A purposive sample of twenty-six (26) English language teachers at Najran university representing the main participants in this paper. The paper revealed that the main cross-linguistic factors affecting interlanguage system progress of Saudi learners of EFL were attributed to the status of English as a foreign language in KSA which doesn’t allow learners ample exposure to communicative language settings, besides the teaching practices that fail in providing authentic learning atmosphere assisting the progress of learners’ interlanguage system, and the interference of learners’ mother tongue that negatively affects the progress of their interlanguage system
Keywords: Cross-linguistic factors, Interlanguage system, Mother Tongue Interference, Saudi learners