Over the last two decades, a growing body of research has shown positive impacts for task planning in task-based instruction (e.g., Ellis, 2005; Foster & Skehan, 1996). However, what learners plan during pretask planning, and whether any specific planning strategies are more beneficial in encouraging learners to attend to linguistic forms and facilitating second language development, have not been systematically investigated. The present study examined the effects of pretask modeling as a planning strategy on learners' attention to question structures and their subsequent question development. Korean junior high school students from two classes were assigned to either pretask modeling or no modeling groups. They completed a pretest, three tasks in pairs, and two posttests over a period of 5 weeks. The modeling group viewed pretask modeling videos as a part of their guided planning, whereas the no modeling group was provided with unguided planning time. The individual learners' think-aloud protocols during planning time and learner–learner interaction during task performance were audio-recorded, and the data were analyzed in terms of language-related episodes. Question development was determined based on Pienemann and Johnston's (1987) developmental sequence. Results indicate that pretask modeling facilitated learners' attention to form, especially during planning time, and their question development.