Purpose: This study examines the absolute and relative effects of 3 different treatment programs for school-age bilingual children with primary or specific language impairment (PLI). It serves to expand the evidence base on which service providers can base treatment decisions. It also explores hypothesized relations between languages and cognition in bilinguals with PLI. Method: Fifty-nine school-age Spanish-English bilingual children with PLI were assigned to receive nonlinguistic cognitive processing, English, bilingual (Spanish-English), or deferred treatment. Participants in each of the 3 active treatments received treatment administered by nationally certified speech-language pathologists. Pre- and post-treatment assessments measured change in nonlinguistic cognitive processing, English, and Spanish skills, and analyses examined change within and across both treatment groups and skill domains. Results: All active treatment groups made significant pre- to post-treatment improvement on multiple outcome measures. There were fewer significant changes in Spanish than in English across groups. Between-group comparisons indicate that the active treatment groups generally outperformed the deferred treatment control, reaching statistical significance for 2 tasks. Conclusion: Results provide insight into cross-language transfer in bilingual children and advance understanding of the general PLI profile with respect to relationships between basic cognitive processing and higher level language skills.