This study presents a cross-linguistic analysis of the use of past tenses in English and Vietnamese by freshmen at Vinh University. The findings reveal that students struggle to use English past tenses correctly, mainly due to structural differences between the two languages and the influence of their mother tongue. Data collected from surveys, grammar exercises, and student writings indicate common errors in using complex tenses such as the past perfect continuous. The study recommends enhancing grammar instruction, adopting interactive learning strategies, and increasing exposure to real-life contexts to improve students' use of past tenses.