The  aim  of  the  current  study  was  to  explore  whether  lexical  processing  in  a  bilingual’s  first language (L1) can be influenced by recent experience in their second language (L2). We focussed on word forms that exist in both their languages, and have either the same meaning (cognates) or a different meaning (interlingual homographs). Our previous experiments provided evidence for the reverse form of cross-lingual priming: processing of interlingual homographs in a bilingual’s L2 is delayed by recent experience with these words in their L1, while processing of cognates can be speeded up (Poort et al., 2016; Poort & Rodd, 2019b). In the current experiment, Dutch–English bilinguals (n = 106) first encountered cognates (n = 50), interlingual homographs (n = 50) and translation  equivalents  (n = 50)  embedded  in  English  sentences.  After  a  15  minute  delay  they  made Dutch semantic relatedness judgements to these target words. Significant cross-lingual priming was observed for the interlingual homographs, but not for the cognates. The magnitude of  this  L2-to-L1  priming  effect  did  not  differ  from  our  earlier  L1-to-L2  priming  effect  (Poort  &  Rodd, 2019b). We also addressed subsidiary questions regarding the (unprimed) processing of cognates  and  interlingual  homographs.  Consistent  with  our  previous  findings  (Poort  &  Rodd,  2019b), we found a large interlingual homograph inhibition effect in an L1 semantic relatedness task,  but  no  evidence  for  a  cognate  facilitation  effect  in  this  task.  These  findings  together  emphasise the high level of cross-lingual interaction in the bilingual mental lexicon, especially in language-switching contexts.