Initially, the third-generation Sienna debuted with a four-cylinder engine option—a notable shift since Toyota had not offered such an engine choice in the previous models since discontinuing the Previa in the late 1990s. This move aimed to improve fuel efficiency while providing sufficient power for everyday driving needs. However, in the 2013 model update, the four-cylinder engine was phased out, shifting focus toward more powerful and refined powertrains.

This generation is characterized by numerous technological and comfort enhancements. A highlight is the availability of an optional second-row seating that features plush, lounge-like recliner chairs, transforming the cabin into a luxurious relaxation zone. The infotainment system was also upgraded significantly, with larger LCD screens offering both widescreen and split-screen options, elevating rear-seat entertainment to new heights. The 2012 model introduced Toyota's Entune navigation system as a standard feature in the top-tier XL 30 trim, enhancing connectivity and navigation capabilities for drivers and passengers alike.

Throughout the 2015 model year, the Sienna received subtle exterior updates, including minor design refreshes and the addition of new color options, catering to consumer preferences for modern stylings and personalization choices. These aesthetic updates complemented the vehicle’s already robust suite of safety and convenience features, making it an appealing choice among family minivans.

Safety features were a primary focus during this generation. Notable innovations included a 180-degree panoramic view camera, which significantly improved visibility and maneuvering, especially in tight spaces. The vehicle also incorporated a driver’s knee airbag and an advanced vehicle stability control system to enhance occupant protection. Additional safety upgrades, such as automatic high beam dimmers and a pre-collision system, contributed to the vehicle's strong safety ratings, consistently earning 'good' ratings in crash tests, which is critical for family transportation.

One of the most distinctive features of the Toyota Sienna during this period was its commitment to accessibility. Toyota was the only major automaker offering an auto-access seat designed explicitly for disabled passengers, available as an optional feature. This innovation underscored Toyota’s dedication to inclusivity, making the Sienna not only family-friendly but also accessible to individuals with mobility challenges.

The 2017 model brought further enhancements, notably an upgraded eight-speed automatic transmission that provided smoother shifting and better fuel efficiency. Power was increased to 296 horsepower, with torque rising to 263 lb.ft, offering improved acceleration and driving dynamics. Additionally, the integration of Toyota’s direct injection fuel system helped optimize engine performance, ensuring better fuel economy and reduced emissions, aligning with the latest environmental standards.