In the conventional classroom, many obstacles hinder interaction between an instructor and students, such as limited class hours, fixed seating, and inadequate time for meetings after class. This work develops a novel multimedia mobile classroom feedback system (MMCFS) that instantly displays students' responses, such as class-related questions or answers to questions on a quiz, on the instructor's computer. This system reinforces interaction between instructors and students and improves learning efficiency. Its features are as follows: 1) automatic attendance checking; 2) in-class real-time evaluation; 3) improved willingness of students to raise questions; 4) immediate grade enquiring; 5) cross-platform functionality; 6) a virtual mobile classroom; 7) data integrity; 8) low construction cost; 9) group learning; and 10) learning process recording. This system uses a client-server and three-tiered architecture models as its framework. When a class is in progress, the instructor only requires a notebook computer with a web browser, while students need a mobile phone or equivalent mobile devices with built-in Java Platform, Micro Edition (J2ME) and wireless support. A web server and the rear-end database can be located outside the classroom when network connections are available. Attendance checking, conducting quizzes, instant question inquiring, and grade inquiring are the four primary functions of the system. A questionnaire is applied to evaluate system's interactivity, mobility, and functionality. The 105 subjects comprised two classes of undergraduate students. The questionnaire addresses interactivity, mobility, and functionality. Its purpose was to compare the proposed system and the interactive response system (IRS). Experimental results show that the proposed system has superior interactivity, mobility, and functionality.