Most international adoptees (IA) have rapid catch-up of the delays common at arrival. However, it is not known whether development at arrival predicts later abilities or school readiness. Therefore, we comprehensively evaluated language, fine motor, visual reception (VR), executive function (EF), attention (ATT), and sensory skills (SS) in IA preschoolers. We hypothesized that pre-adoptive risk factors, development at arrival, and the post-adoptive environment (time in day care) would predict developmental and behavioral outcomes and school readiness. 37 IA (12M:25F), currently age 4-5 years and previously seen in our clinic (mean arrival age 12 months), were evaluated with standardized tests of development, language, EF, ATT, and SS, along with demographic information, parent interview, and review of arrival clinic records. Fine motor and VR skills at arrival ranged from average to very below average. At followup, most IA were average or above average in fine motor, VR, and language skills, but many had concerning scores for ATT (42%), EF (11%) and SS (48%). Arrival expressive language T scores (Mullen) predicted follow-up scores for expressive language (PLS-4, r = .44, p = .005). Arrival fine motor scores (Mullen) correlated with follow-up auditory comprehension scores (PLS-4, r = .47, p = .002) and inversely with inattention scores (Conners', r = -.48, p = .003). Arrival visual reception scores correlated inversely with global measures of attention (Conners' opposition r = -.45, p = .005, ADHD scores r = -.49, p = .002, and to a lesser extent hyperactivity r = -.35, p = .03). Age at arrival was a very strong predictor of many of the outcome measures tested, including language performance, attention regulation, executive function, and sensory processing. Children who spent more time in daycare had significantly more difficulty with emotional control (p = .005). Although IA have good catch-up in specific areas of development, difficulties with ATT regulation, EF, and sensory processing may increase the risk of later school problems.