International Program for Islamic Economics and Finance (IPIEF) of Universitas Muhammadiyah Yogyakarta has a vision to become a leading international program in ASEAN by 2021. So, the IPIEF students are expected to be fluent in English both spoken and written. Therefore, in order to enhance the fluency, English is a compulsory subject should be taken by the students. The research aims to describe the form of grammatical errors made by IPIEF students batch 2017 of Universitas Muhammadiyah Yogyakarta using Surface Strategy Taxonomy. The research was conducted in the English II class named Free Conversation class. The data were collected using recording technique and trancripstions were made after that. Then, the data were analyzed by error analysis and written using qualitative descriptive approach. The result of the research shows: the total errors found was 115 errors, included: 1) the most type of errors appeared in the students‟ speaking are misformation occured for 44.3%; 2) The sources of errors in the students‟ speaking are false concept hypothesis (33%), ignorance hte rule restriction (31.3%), incomplete application of rule (27%), and overgeneralization (8.7%). Based on the result of the research, it is suggested that the students pay attention on the errors and if it necessary they need to look for assistance to practice their speaking skills either from their lecturer or other friends.