In the context of Canada's reliance on immigration for social and economic development, an effective language policy for migrant students is essential for educational systems. However, existing language policy research puts little emphasis on parental agency, particularly immigrant parents. The qualitative study presented here therefore explored how immigrant parents advocated for more equitable English as an Additional Language (EAL) policies and practices in Alberta, Canada. Through document analysis, interviews with 35 immigrant parents and community members as well as two focus group discussions involving parents and policymakers, this study found that many immigrant parents engaged in intentional informal learning (e.g. workshops, role playing) to acquire knowledge of the EAL system and develop advocacy strategies. Exercising parental agency on behalf of their children, they undertook various collaborative as well as individualised strategies to influence EAL policies. This study challenges the deficit perspective and suggests there is a need to recognise immigrant parents as informed policymakers and engage them as collaborators in decision-making to transform schools and educational systems towards educational equity and justice.