This paper reports two experiments on the implicit learning of second language word stress rules and presents a methodological innovation. In both experiments L1 Cantonese L2 English participants practised pronouncing two-syllable Spanish words. Learning of a hidden stress regularity was measured by a judgment task. We assessed participants’ awareness of the stress rule by verbal reports, confidence rating and a novel methodology: inclusion-exclusion production tasks adapted from Destrebecqz and Cleeremans (2001). Experiment 1 demonstrated the implicit learning of association between the ending phoneme and word stress and experiment 2 the implicit learning of a more abstract rule of stress placement. We conclude that L2 word stress rules may be learnt implicitly.