This study aimed to characterize neuropsychological and linguistic skills in children with Developmental Dyslexia (DD) with and without Language Impairment (LI). Behavioral tests of short-term memory, phonemic awareness, and morphosyntactic processing and electrophysiological responses to agreement violations were administered to 32 DD children (16 with additional LI) and 16 controls. Behavioral data revealed quantitative differences among groups: DD+LI children showed the worst performance, followed by DD-only children and controls. Event-related potential results confirmed atypical morphosyntactic processing in the DD-only group, highlighting qualitative differences between groups. These results support multifactor models of learning disabilities, where different patterns of deficits characterize different subgroups.