The purpose of the present mixed methods study was to investigate if enhancing Focus on Form (FonF) tasks with data-driven learning (DDL) affects English as a Foreign Language (EFL) learners' task motivation from the self-determination theory (SDT) perspective. Following a quasi-experimental comparison group pretest-posttest and sequential explanatory mixed methods designs, 76 female English-major university students were randomly assigned to comparison and intervention groups and exposed to the control and treatment, respectively. The control involved completing 15 non-DDL tasks, whereas the treatment was completing 15 DDL-enhanced tasks over a month. The results of a task motivation questionnaire and semi-structured interviews showed that DDL-enhanced tasks increase learners' task motivation from the SDT perspective. In other words, enhancing FonF tasks with DDL leads to more self-determined motivation to perform English tasks. That is, discovery learning which is a kind of self-regulated learning, along with awareness raising, in tasks with authentic language data where the primary attention is on meaning, tends to promote learners' agency, and result in more motivation to learn English. This kind of motivation which seems to be the result of increased achievement in English language skills, autonomous language learning, association with others, internal reward, and usefulness, is most influential, as it is self-determined.