This study examines the evolving acceptance and use of humour in advertising over the past century. Sociologists point to humour as an expression of the macro-societal mood. Consistent with this thesis, we analyse two data sets of outdoor advertisements that span over 100 years. We use a socio-cultural and historical perspective to understand the underlying drivers and changes in humour use at both the macro-cultural level and at the micro-industry level in the US. The results reveal the contextual interplay that led to changes in the acceptance of humorous advertisements as well as the evolution of humour styles and elements.