Through an experiment with adult Koreans learning English as a foreign language, this study gives evidence to the hypothesis that lexical constraints are transferred to interlanguage in learning English double object datives. Previous studies dealing with L2 acquisition of English double object datives largely focus on whether or not L1 transfer occurs at the morphological level. This study attempts to demonstrate that the lexical differences shown in these previous studies reflect the differences in the lexical constraints of Korean and English. For example, observation of the experiment results in Oh & Zubizarreta (2003) reveals there is a lexical difference between whisper and shout. This seems to reflect the grammatical contrast shown in their Korean counterparts when they occur in Korean dative accusative constructions realized as ``-eykey -lul -hata``. Thus the experiment for this study was constructed under the hypothesis that when an adult Korean learns English as a foreign language, L1 transfer occurs at the level of lexicon rather than morphology. The subjects of this experiment were 69 university students majoring in English Language and Literature. They were asked to determine, on a scale of one to five, the grammaticality of twelve sentences, which were divided into four sets of three; sentences that were grammatical in English and Korean, sentences that were grammatical in English but ungrammatical in Korean, sentences that were ungrammatical in English but grammatical in Korean, sentences that were ungrammatical in both English and Korean. However, when the results between sentences that were ungrammatical in English but grammatical in Korean and sentences that were grammatical in English but ungrammatical in Korean are compared, the former has a higher acceptability than the latter, showing that there is a lexical constraint transfer.