The paper explores the adoption of the social dimensions of sustainability in technological design tasks. It uses a lens which contrasts education for sustainability as "a frame of mind" with an attempt to bridge a "value-action gap". This lens is used to analyse the effectiveness of the Sustainable Design Award, an intervention in post-16 technology education in three countries to encourage students and teachers to strengthen design for sustainability in their work. In each country, the intervention project provided varying combinations of teacher professional development, provision of learning resources, in school student support, lobbying of key curriculum policy makers and a student Award. Three types of teacher are identified by reference to their motivation for introducing sustainability into their teaching of design. These teacher types are linked to a hierarchy of teachers' understanding of the social dimension of sustainability. The consequences for continuous professional development are examined. The findings are then used to critique the value of the lens.