With the recent implementation of the K-12 curriculum in the Philippines, kinder to grade 3 used their mother-tongue as a medium of instruction. Teachers are challenged to teach pupils how to read English by the end of grade three and pupils are expected to read English to be promoted to the next grade level. At present, few textbooks and instructional materials are used in teaching especially in reading. This study developed and validated an English reading workbook for grade three based on the curriculum guide, specifically on phonics and word recognition. The design and developmental research was used in this study since it aimed to develop and validate of a grade 3 English reading workbook. The reading workbook was validated by the experts using the two instruments (Evaluation Instrument for topics to be Included in the DE/ODeL and Evaluation Rating Sheet for DE and ODeL Modules) adopted by the College of Education - Pampanga State Agricultural University. Findings revealed that the validators agreed, the develop English reading workbook was valid in terms of content, design/format and pedagogical factors. The researcher used the content validity ratio, frequency, and percentage to interpret the data needed. The validated English reading workbook can be used as an additional instructional material in teaching reading for grade three learners. Further, review and evaluation of the English reading workbook may be considered to make it more contextualized and localized in the Philippine setting. Keywords: reading workbook, curriculum guide, word recognition, instructional material