Previous research has documented the validity of parent report for measuring vocabulary and grammar in typically developing toddlers. In this project, two studies examined the validity of parent report for measuring language in children with specific language delay who are older than the normative group, but who have language levels within the range measured by the instruments. In Study 1, scores on the MacArthur Communicative Development Inventory: Words and Sentences were compared to behavioral measures of production of vocabulary and grammar in 39- to 49-month-old children with language delay. Results indicated moderately high to high concurrent validity correlations in both domains (.67-.86). In Study 2, scores on the MacArthur Communicative Inventory: Words and Gestures were compared to behavioral measures of vocabulary comprehension and production and gesture production in 24- to 32-month-old children with language delay. Results indicated a moderately high concurrent validity correlation for vocabulary production (.66). Parent report of comprehension and gesture scores did not correlate significantly with their behavioral counterparts, but gesture scores were moderately highly correlated with language comprehension (.65).