When derived stimulus relations are established, stimulus functions are altered. The present study aimed to verify whether arbitrary symbols related to meaningful stimuli (facial expressions of happiness) would have their meaning transformed in accordance with relations of sameness or opposition. The experiment started with training to establish the meaning of two contextual cues, one for sameness and one for opposition. Then, using these contextual cues, one pair of stimuli was related as same (B1) or opposite (B2) to six photos containing different people expressing happiness (A stimulus set, A1-A6). Following this training, two other stimuli were related as same (C1) and opposite (C2), respectively, to B1. Participants were tested for derived relations and then the transformation of functions from the happy pictures to B1, B2, C1, and C2 was verified using a semantic differential and the Implicit Relational Assessment Procedure (IRAP). Results from the semantic differential happy/sad scale, taken together with IRAP, indicated the transformation of stimulus functions: Arbitrary stimuli acquired a meaning similar or opposite to the happy faces, according to the trained or derived relations of sameness or opposition.