This study focused on digital storytelling (DST) as a task in technology-mediated task-based language teaching and examined its effects on English speaking proficiency, willingness to communicate in English (WTCE), and group cohesion (GC). Two intact classes of Taiwanese EFL students, either as the DST group or as the comparison group, first responded to the WTCE scale, the GC scale, and a standardized English speaking test. Next, the DST group completed two DST tasks, each of which entailed locating information, generating the story script, obtaining visual and aural support, rehearsing and recording the oral reading, combining the visual and aural support with the audio recording to create the digital story, and playing the digital story and then telling the story again with the muted digital story in class. During the weeks when the DST group presented digital stories, the comparison group watched and discussed movies and composed a reflective report in English. Finally, both groups responded to the WTCE scale and GC scale again and took another set of the standardized English speaking test. Data analyses disclosed that DST tasks significantly increased English speaking proficiency and GC but affected WTCE in a positive yet nonsignificant manner.