Word learning is guided by the statistical co-occurrence between spoken words and potential referents, through which learners gradually map labels to objects across situations. Given that word learning does not occur in a vacuum, rather in a communicative context, it is relevant to evaluate the role that speakers play. Because we do not evaluate the information provided by every person equally, it is reasonable to think that someone who makes lexical errors is not a reliable speaker from whom to learn new words. The current study focuses on speaker reliability in adult cross-situational word learning (CSWL). In two experiments we investigated the extent to  which  adults  attend  to  the  reliability  of  the  speaker  and  how  this  affects  word  learning  in  a CSWL task. We varied the consistency with which a speaker mapped novel words to familiar objects. We hypothesized (1) that the speakers’ reliability would be judged differently depending on their past object-labeling accuracy, and (2) that new words would be more difficult to learn when  presented  by  an  unreliable  speaker.  Experiment  1  shows  that  the  unreliable  speaker  was  assessed  as  less  reliable,  compared  to  the  reliable  speaker,  but  this  effect  disappeared  in  Experiment  2,  when  participants  were  taught  new  words  by  two  speakers,  a  reliable  and  an  unreliable  one.  Furthermore,  we  found  no  evidence  to  support  the  hypothesis  that  being  exposed  to  an  unreliable  speaker  impairs  CSWL  in  adults.  We  discuss  the  relevance  of  these  findings and the importance of further research on the role of speaker reliability in CSWL.