Two studies are presented on expressive happy and sad drawings made by British 4‐ to 12‐year‐olds (n = 80 and 160, respectively) in which the drawings were assessed individually for the quantity and quality of expressive devices. Quantity was measured in the number of appropriate expressive content themes and formal properties evident in each drawing. Quality was rated on a Likert scale on the extent to which the drawing expressed the intended mood. Both the quantity and quality of expressive happy and sad drawings of predetermined and free topics increased with age. Improvements in content expression, but much less so with expressive formal properties, accounted for the development of quantity. A slower period of development between 6 and 9 years for both measures was consistently found, with a significant improvement often shown among the 12‐year‐olds. The finding that happy drawings were scored higher than sad drawings is explained in respect of adult and child expectations of pictures. Correlations between expressive scores and performance on a visual realism drawing task tentatively indicated that expressive and realism skills in drawing are only weakly related. The development of expressive drawing is considered in the context of the delivery of art education in schools.