Purpose: The purpose of this study was to examine the association of speech-sound disorders (SSD) with symptoms of attention-deficit/hyperactivity disorder (ADHD) by the severity of the SSD and the mode of transmission of SSD within the pedigrees of children with SSD. Participants and Methods: The participants were 412 children who were enrolled in a longitudinal family study of SSD. Children were grouped on the basis of the severity of their SSD as determined by their scores on the Goldman-Fristoe Test of Articulation and history of an SSD. Five severity groups were compared: no SSD, resolved SSD, mild SSD, mild-moderate SSD, and moderate-severe SSD. Participants were also coded for comorbid language impairment (LI), based on scores on a standardized language test. Pedigrees of children were considered to represent bilineal inheritance of disorders if there was a history for SSD on both the maternal and paternal sides of the family. Parents completed the ADHD rating scale and a developmental questionnaire for each of their children. Results and Conclusions: Children with moderate-severe SSD had higher ratings on the inattention and hyperactive/impulsivity scales than children with no SSD. Children whose family pedigrees demonstrated bilineal inheritance had higher ratings of inattention than children without bilineal inheritance. To determine the best predictors of ADHD ratings, multiple linear regression analyses were conducted. LI was more predictive of ADHD symptoms than SSD severity, bilineal inheritance of SSD, age, or gender. Findings support that LI rather than SSD is associated with ADHD.