This study investigated the acquisition of English slang in a foreign language context. The participants were 101 Bulgarian learners of English, 58 high school students, and 43 university students. The instrument included knowledge tests of English slang terms and questions about attitudes, sources, reasons, and methods employed in learning English as a foreign language slang. The data were analyzed through multivariate analyses of variance, discriminant function analysis, and qualitative analyses. The younger group was significantly associated with the knowledge of vulgar/offensive slang, λ= .374, χ2(12) = 91.47, p < .001. The same group showed a significantly higher appreciation of slang as a way of group belonging and projecting an image of looking cool. Overall, there were quantitative and qualitative differences between the age groups on all variables of interest, which are interpreted in view of sociopsychological factors.