Since moving to Oklahoma City in 2008, the Thunder have always had a top point guard, and Russell Westbrook undisputedly occupies the top five in the single-season assists per game list.

Topping the list is Westbrook in the 2018-19 season, who averaged 10.7 assists per game, not only breaking his personal record but also leading the league. This was also his third consecutive season averaging a triple-double (22.9 points, 11.1 rebounds, 10.7 assists) before being traded to the Houston Rockets after the season.

The second and third places came from the 2015-16 and 2016-17 seasons, with Westbrook averaging 10.4 assists per game in both seasons. In 2016, he was second only to Rondo in assists and was selected to the All-NBA First Team for the first time.

In 2017, Westbrook averaged a triple-double (31.6 points, 10.7 rebounds, 10.4 assists) for the first time in a season since Oscar Robertson in 1962, and won the regular season MVP.

Fourth place is 10.3 assists in the 2017-18 season. That year Westbrook was crowned the assist king for the first time, and it was also his second consecutive triple-double (25.4 points, 10.1 rebounds, and 10.3 assists).

The fifth highest average was 8.6 assists in the 2014-15 season, which was a personal high for Westbrook and ranked fourth in the league. He also won the scoring title with an average of 28.6 points per game and finished fourth in the MVP voting.

This list not only reflects Westbrook's consistent, high-level playmaking ability, but also testifies to his all-around performance during his time with the Oklahoma City Thunder. Averaging a triple-double for three consecutive seasons, winning regular season MVP, the scoring title, and the assists title, he has become one of the most iconic players in franchise history.