This study analyzes question formation errors in English made by EFL majors in Najran University – KSA. The aim of the study is to find out the types and causes behind making such errors. For this purpose, the researcher has designed a wh-question generating instrument. After identifying the categories of errors, the data analysis has shown agreement with similar previous studies. The most common error types in forming wh-questions in English are: auxiliary omission, wrong question word, aux.-subject inversion, Wrong auxiliary and many others.Our study has also revealed that some of the errors are due to grammar incompetence required for question formation, while others can be attributed to structure dissimilarities of the two languages.