Teachers must foster within themselves the idea that technology is a part of civilization that must inevitably go hand in hand with teaching and learning, including assessment. Technology-based assessment should assist teachers in dealing with digital native students who are already aware of their own needs, requiring teachers to integrate differentiated instruction. This qualitative study reported EFL teachers' perceptions and challenges regarding technology-based assessment for learning (AfL) and assessment as learning (AaL) within the differentiated instruction framework. Gathering the data involved conducting structured interviews with 60 EFL teachers hailing from Yogyakarta, Indonesia, and utilizing the grounded theory framework as the analytical foundation. This study used content analysis. The transcribed interview data underwent coding through a systematic step-by-step process. It involved repeatedly reviewing the data to identify common patterns and recurring themes. The findings showed that EFL teachers had different perspectives about technology-based AfL and AaL within English-differentiated instruction. Most EFL teachers could be better at giving feedback after using the AfL process. They need more time to prepare technology-based AfL and AaL for differentiated instruction and group students based on their needs and abilities. Internet connectivity disrupts student engagement. Teachers mainly focus on professional development activities. The study suggests that EFL teachers and trainers should use a technology-based model for AfL and AaL to support differentiated instruction.