This study investigated the effectiveness of Online Dynamic Assessment in improving listening comprehension skills of engineering students. The study employed two instruments: Listening Comprehension Skills Checklist; and Listening comprehension Skills Test. The checklist was intended to determine the most important listening comprehension skills required for engineering students. Hence, it was administered to a sample (n=30) that included 10 engineering students,10 in-service engineers and 10 staff members of English as a Foreign Language and English for Specific Purposes. This study adopted the pre/post-test one group quasi-experimental design. The proposed program was applied on a sample of 16 students at the second year of the College of Engineering and Technology, Arab Academy for Science Technology and Maritime Transport. The program lasted for 9 weeks. Then to measure its effectiveness, subjects' mean ranks on the pre-program administration of listening comprehension skills test were compared with their mean ranks on the post-program administration of the same test. The results indicated a significant improvement in engineering students' listening comprehension skills. This improvement can be interpreted in the favour of the effectiveness of the online dynamic assessment proposed program.