Reading engagement is crucial to motivating EFL learners in reading classes. Recent research has attempted to explore the effect of affective engagement on reading comprehension, but there exists little empirical research regarding the effect of a text-driven approach to task design and development that draws on second language acquisition principles including both emotional and cognitive engagement. The current quasi-experimental study was conducted to investigate its effect on EFL learners' reading comprehension. The study involved 62 Vietnamese EFL teenage learners (aged from 14 to 16) from two intact classes at an English language center in the Mekong Delta of Vietnam. One class with 31 learners was assigned to the experimental group whose reading lessons employed a text-driven framework for adapting tasks from a textbook used by the center. The other class, who followed reading activities provided in the textbook, was treated as the control group. Two reading comprehension tests, a pretest and a posttest, were administered before and after a 13-week intervention. The results showed that the experimental group outperformed the control group on the reading comprehension posttest. In interviews with selected learners, they also reported feeling more engaged and motivated to read.