This research is a study of the manuscript of Tafsīr al-Jalālayn found in Tegalsari Islamic boarding school, Jetis sub-district, Ponorogo district, East Java province, which is then called "Manuscript of Tafsīr al-Jalālayn Tegalsari". This research will focus on the historical aspects of writing the Tegalsari Tafsīr al-Jalālayn manuscript and the characteristics of the Tegalsari Tafsīr al-Jalālayn manuscript in terms of philological aspects. This research is classified as a qualitative research model that is field research with descriptive analysis techniques. Based on the research that has been carried out, it produces two conclusions. First, the manuscript of Tafsīr al-Jalālayn Tegalsari was written by Muhammad Jalalain, the fifth descendant of Kiai Ageng Muhammad Besari. Second, from the codicological aspect, the manuscript of Tafsīr al-Jalālayn Tegalsari was written on paper produced in Tegalsari village around the 18th-19th centuries AD, called gedhog (dluwang) paper, written in red and black ink and using the type of khat Riq'ah. The manuscript consists of two volumes, the first volume is 36 cm long, 22.5 cm wide, 3.5 cm thick and has 406 pages. The second volume is 37.5 cm long, 13.5 cm wide, 4 cm thick and has 382 pages. Thus the total number of pages of this manuscript is 788 pages with each volume having 16 kuras. This manuscript has also been digitized and can be accessed through the Endangered Archive Programme (EAP) with code number EAP061-3. Based on the textological aspects in this manuscript, there are scholia of error correction in Tafsīr, scholia of additional verses in the Qur'an, scholia of additional verses in tafsīr, scholia of additional verses in the Qur'an and tafsīr, scholia of the word alihan and scholia of the beginning of juz. In addition, this manuscript also uses syakl or punctuation marks that are commonly used, there are rukuk symbols, reference symbols and symbols for correcting errors or adding lafādz to the text, and there are also some corruptions in letters, words, sentences and harakat.