The past tense acquisition has always been a challenging task for the Second Language (L2) learners. The challenge resides in conveying ideas, thoughts, and opinions either in spoken or written production. This study attempts to designate and classify the causes of morphological errors committed by Moroccan EFL learners’. The focus is on factors that augment morphological errors more precisely in students’ written productions. Corder’s (1974) Error Analysis is adopted to evaluate and measure the errors spotted in learners’ essays. The subjects who participated in this investigation are 120 Moroccan engineering students at ENSET Mohammedia, Hassan II University. The findings demonstrate that a) the students’ English morphological appropriateness is low b) the learners overgeneralize the rule of the regular past tense over the irregular. Even though the participants’ levels vary between beginners and pre-intermediate English language level according to the placement test. English inconsistency, misuse of rules, and language interference are the main factors causing such errors. This paper suggests that English language instructors need to pay close attention to learners’ language proficiency. It is quite impossible to eradicate all of the learners’ errors. Yet, a meticulous explanation by providing a semantic context of verbs could help reduce students’ errors.