Metal-insulator-metal (MIM) capacitors with insulator stacks having a plurality of metal oxide layers are described. For example, a MIM capacitor for a semiconductor device includes a trench disposed in a dielectric layer disposed above a substrate. A first metal plate is disposed along the bottom and sidewalls of the trench. An insulator stack is disposed above and conformal with the first metal plate. The insulator stack includes a first metal oxide layer having a first dielectric constant and a second metal oxide layer having a second dielectric constant. The first dielectric constant is higher than the second dielectric constant. The MIM capacitor also includes a second metal plate disposed above and conformal with the insulator stack.