Inside, the 2007 Kia Optima offers a spacious and comfortable cabin. It has seating for five passengers, with generous legroom and headroom in both the front and rear seats. The materials used in the interior are of decent quality, but some hard plastic surfaces are present. Overall, the fit and finish are commendable for a car of this class and price range.

In terms of features, the 2007 Kia Optima comes well-equipped for its time. Depending on the trim level, it may include amenities such as power windows and mirrors, heated front seats, leather upholstery, automatic climate control, a power sunroof, and a premium audio system. Safety features can include front and side airbags, anti-lock brakes (ABS), traction control, and stability control.