The purpose of this study was to investigate the impact of a mobile-assisted dialect awareness programme on the dialect attitudes of pre-service English language teachers in Turkey. The study adopted a pre-test and a post-test design including 58 first-grade pre-service English language teachers in two different classes. The experimental group received dialect awareness training supported with WhatsApp for 14 weeks, while the control group received no training. Data were collected via a verbal guise test for evaluating the change in the participants' attitudes of Russian, British, Turkish, American and Arabic dialects of English. Dialect awareness training promoted positive attitudes towards all dialects but British, which received the higher scores prior to the treatment in terms of solidarity, power and speech quality. These results suggest that language teacher training in linguistic variation has the potential to empower teachers to appreciate and tolerate non-standardised dialects in addition to long adored standardised dialects.