Purpose: This study tested children's sensitivity to tense/agreement information in fronted auxiliaries during online comprehension of questions (e.g., "Are the nice little dogs running?"). Data from children with developmental language disorder (DLD) were compared to previously published data from typically developing (TD) children matched according to sentence comprehension test scores. Method: Fifteen 5-year-old children with DLD and fifteen 3-year-old TD children participated in a looking-while-listening task. Children viewed pairs of pictures, 1 with a single agent and 1 with multiple agents, accompanied by a sentence with a fronted auxiliary ("is" + single agent or "are" + two agents) or a control sentence. Proportion looking to the target was measured. Results: Children with DLD did not show anticipatory looking based on the number information contained in the auxiliary ("is" or "are") as the younger TD children had. Both groups showed significant increases in looking to the target upon hearing the subject noun (e.g., "dogs"). Conclusions: Despite the groups' similar sentence comprehension abilities and ability to accurately respond to the information provided by the subject noun, children with DLD did not show sensitivity to number information on the fronted auxiliary. This insensitivity is considered in light of these children's weaker command of tense/agreement forms in their speech. Specifically, we consider the possibility that failure to grasp the relation between the subject-verb sequence (e.g., "dogs running") and preceding information (e.g., "are") in questions in the input contributes to the protracted inconsistency in producing auxiliary forms in obligatory contexts by children with DLD.