Abstract This study employed research and development design to identify the writing errors of 35 Senior High School students under the Technical Vocational Livelihood Track in one of the public schools in Magalang, Pampanga during the school year 2022-2023. Error analysis was employed in collecting, identifying, describing, and explaining the errors committed by the participants. The errors were classified using the Surface Structure Taxonomy by Dulay, Burt, and Krashen (1982), namely, omission eror, addition error, misformation error, and misordering errOr. Findings revealed that misformation of word (MFW), misformation of capitalization (MOC), omission of punctuation (OP), misformation of verb (MFV), misformation of auxiliary verb and linking verb (MFBV). and misformation of necessary items (ONI) were the most frequently committed writing errors of the students in their academic essays. With the results, the researcher designed a learning worktext in grammar. The learning worktext was validated by two (2) Master teachers in English and three (3) English faculty experts from the Department of Education. Results showed that the content, format, presentation, organization, accuracy, and up-to-datedness of the crafted learning worktext passed the criteria of the evaluation rating tool. Moreover, the learning worktext in grammar may be utilized by the Senior High School teachers to serve as a supplementary learning material for the students and to validate its effectiveness. Keywords: Surface Structure Taxonomy, error, error analysis, learning worktext, grammar.