This study investigated morphological errors made by EFL students in English writing
and the factors influencing these errors. This study employed a descriptive qualitative
design using an error analysis approach. The participants were second-semester students
of the English Education Study Program at Universitas Indo Global Mandiri. The data
were collected through a writing test and an open-ended questionnaire. The findings
revealed four types of morphological errors based on the Surface Strategy Taxonomy,
namely omission, addition, misformation, and misordering. Among these error types,
omission appeared as the most dominant error, indicating that students experienced
difficulties in applying required morphological elements, particularly inflectional and
derivational morphemes. The questionnaire results showed that students’ morphological
errors were influenced by several factors, including mother tongue interference,
difficulties in understanding English tenses, limited grammatical knowledge,
inconsistency in applying language rules, and difficulties in word formation. These
findings indicate that EFL students still face challenges in applying English
morphological rules accurately during writing. Therefore, explicit instruction on
morphology, particularly affixation, word formation, and grammatical markers, is
important to improve students’ morphological awareness and writing accuracy.