Across curricular terrains in education in North America, the use of the term "inquiry" has become more prevalent than ever. This radical turn from traditional content curriculum toward inquiry-based approaches to teaching raises issues about the promise and potential challenges of contemporary curriculum in K-12 L2 settings. This explorative qualitative study investigated the following research question: What are the opportunities and challenges for inquiry-based approaches to English language learners' (ELLs) language, literacies, and content learning, as mandated in twenty-first-century curriculum? Semi-structured interviews, with eight expert language and literacy educators, were conducted to generate data and a thematic analysis of the data was undertaken. The recursive analysis revealed three themes concerning opportunities afforded by an inquiry-based approach: enhance ELLs' understanding of content knowledge, give prominence to ELLs' languages and literacies and promote respect for diversity, and utilize digital tools to support ELLs' language and content learning and amplify their voices. Three themes concerning challenges emerged: educator resistance to change, underestimating required resources, and communicating with parents/guardians of ELLs. Implications are discussed for policy and practices regarding inquiry-based pedagogies, multimodalities, and multilingualism in supporting English learner success.