Demands that Initial Teacher Education (ITE) prepare teachers who can equip students to be agile real-world problem solvers are frequent. Guidance about ITE integrated curriculum approaches to achieve this aim is harder to find, a significant gap given increasing time and policy pressures for ITE educators. Drawing from an Australian context, this systematic review investigates how integrated curriculum is conceptualised and enacted in secondary schooling ITE courses. Three conceptions of integrated curriculum for ITE are highlighted -- Interdisciplinary, Disciplinary Literacy, and Transdisciplinary approaches -- alongside benefits and barriers to enacting integrated curriculum. Recommendations for further research and practice around integrated curriculum are proposed.