The research studied the effectiveness of a three-stage Seamless Learning Model with Enhanced Web-Quizzing based on the intensive use of sets of quizzes created in different web-based quiz generators. The findings revealed that continuous testing using diagnostic, formative, benchmark and summative quizzes, administered at the three stages—familiarisation, formation and assessment, applying such features of seamless learning as learning in various contexts, ubiquitous access to digital learning resources and quizzes, combination of teacher-guided learning, self-directed and collaborative learning, and switching between various learning activities can be an efficient teaching technique in higher education having positive effect on academic performance, motivation, learners’ approaches to studying and course engagement. The testing effect was investigated on the summative tests taken at the end of the three different academic courses. The results showed that online quizzes applied primarily as learning tools with the emphasis on information retrieval and retention resulted in the higher achievements of the experimental group students. The survey conducted with Biggs’s Revised Two-Factor Study Process Questionnaire (R-SPQ-2F) showed the changes in the learners’ motives and approaches to studying revealed in students’ active participation in in-class and out-of-class activities, mastering of the material through understanding rather than mechanical memorizing, the search for additional information and increased attendance. The engagement of the experimental group students in the new quiz-enhanced settings was examined focusing on emotional, skills, participation and performance engagement aspects.