This article assesses the influence of L1 intralexical knowledge on the formation of L2 intralexical collocations. Two tests, a primed lexical decision task (LDT) and a test of receptive collocational knowledge, were administered to a group of non-native speakers (NNSs) (L1 Swedish), with native speakers (NSs) of English serving as controls on the LDT. The tests assessed collocations in three critical conditions: (i) collocations with translation equivalents in Swedish and English (L1-L2), (ii) collocations that were acceptable in English but not in Swedish (L2-only), and (iii) unrelated items for baseline data. Our results showed that the L1 may have considerable influence on the development of L2 collocational knowledge. NNSs both processed [with faster reaction times (RTs) on the LDT] and recognized (with higher receptive scores) L1-L2 collocations more effectively than L2-only collocations. However, the results of the LDT also showed considerable variability for the L2-only condition, suggesting that the overall slower RTs in this condition might have been linked more to a lack of priming for individual items rather than slower RTs for this condition as a whole.