The current research paper was carried out at a university in Hanoi, Vietnam in order to investigate the effects of misconceptions between Vietnamese syntactic concepts and those in English on writing performance. The design of the study was “qualitative case study”. The case was selected from 116 students who have finished their first year studying in different disciplines such as Business Administration, International Business, Banking and Tourism Administration … The scope of the study was the misconceptions on syntactic terms in three categories; verb-related, noun-related and adverbial related errors. The findings were that the verb-related errors such as wrong tenses, infinitive phrases and omission of ‘be’ are frequently found; 31.9%, 30.9% and 29.3% respectively. The errors related to determiners and conjuncts make up 47.8% each. Most of the participants do not understand the meaning of syntactic terms in English. The findings also reveal that some students had poor understanding of the terms just because they did not understand the terms even in Vietnamese language. They are unaware of the importance of the comprehension of the terms in writing English composition. Many of them use the terms by their ‘hunch or afflatus’. Some said that their teachers’ explanations of Vietnamese syntactic terms were varied and difficult to generalize