Nowadays, teachers use various materials not only sourced from textbooks because teachers feel that textbooks still need material from other sources to support learning, which is called supplementary material. Supplementary material is needed as additional material and is sometimes used as the main source of learning English. This research was conducted to determine what Supplementary materials were used and how they were implemented in the classroom.

This research used qualitative descriptive methods to provide comprehensive-textual descriptions of the use of supplementary material by the English teacher in the eleventh grade at SMAN 4 Banjarmasin.  The research subjects are “teacher 1” and “teacher 2”, English teachers in grade 11 of SMAN 4 Banjarmasin and have experienced teaching using supplementary materials in the classroom. The primary data was collected through observation, while secondary data was collected through interviews and video recordings.

The supplementary materials used by English teachers to teach eleventh-grade students at SMAN 4 Banjarmasin are essential and generally in the form of printed and internet-based materials, with printed supplementary materials in the form of workbooks used to make it easier for students to understand the learning as they only present the core material of the discussion topic. Meanwhile, supplementary internet-based materials in the form of selected internet-based materials and YouTube videos were used to increase students' enthusiasm for learning and deepen their understanding of the material being taught.

It is suggested for teacher to consider the criteria of selection of teaching learning material before implementing the supplementary material in the classroom. It is also recommended for further research focus more on how students respond to the implementation of supplementary materials by the English teacher in the classroom.