Robert G. "Bob" Kloppenburg (born July 28, 1927) is an American professional basketball coach, who served as an interim head coach of the Cleveland Cavaliers in the early 1980s. Kloppenburg later served as an assistant coach for the Seattle SuperSonics, Denver Nuggets and Toronto Raptors. While with the Seattle SuperSonics (1985–1996), Kloppenburg was the assistant coach for the NBA West All-Star team in 1994. He contributed to Seattle's three 60 win seasons in the 90's. His NAIA small college coaching career saw him win five district championships in twenty years for an overall record of 369-161. Widely regarded as the innovator of the SOS Defensive System, a system known for its ability to create turnovers because of "contact switching" on every screen and intense ball pressure with trapping principles. Kloppenburg is, together with Ernie Woods, the co-founder of basketball coaching website HoopTactics.com.
Kloppenburg played college ball at the University of Southern California with the famous proponent of the modern Triangle offense, Tex Winter. SOS Defensive System is used worldwide. Bob Kloppenburg has coached and taught other the "how to's" of the game for four decades at the entry level from high school to the pros. His defensive oriented teams have been consistent winners, and his reputation as an outstanding defensive coach and teacher, both at home and abroad, has taken him to 14+ countries around the globe to teach his system of defense. Now retired from active coaching, he is still effectively teaching his "SOS" defensive strategies to coaches with his same patent vim, vigor, and vitality. Kloppenburg has been married for over 60 years to Gayle Kloppenburg. Together they have two children, Gary and Kim. They also have six grandchildren: Sonja, Ian, Carlotta, Paige, Gabe, and Tess as well as two great grandchildren: Kyson and Kameron.
He attended John Marshall High School in Los Angeles, leading his basketball team to the Los Angeles City Championship, in a season in which he was named the Southern California High School Player of the Year. He was named to the charter class of the school's basketball Hall of Fame, and was inducted in its first ever Athletic Hall of Fame on June 15, 2012.
- "Bob Kloppenburg is a defensive genius. I know! I have to coach against him." - Pat Riley
- "During my basketball career. I have been very fortunate in working with some outstanding defensive coaches. Bob Kloppenburg, beyond doubt, is one of the best. His breakdown drills, philosophy, and the intensity he extracts from defensive personnel make his book worth reading for all levels of coaching." - Bernie Bickerstaff
- "Coach Kloppenburg has been one of the truly outstanding teachers in basketball for many years. Few are as advanced in their thinking in today's basketball as Coach Kloppenburg." - Pete Newell
- "Coach Kloppenburg has created a system that can work on any level. His defensive philosophies are a major reason for our success with the Sonics. He has an answer for every situation, and it can be taught very easily. Finally, it is a system that makes the game fun and one that the team, coach and players can believe in." - George Karl
- "SOS Pressure Defense is a masterpiece of work done by one of the great tacticians in the game of basketball. Kloppenburg has hit a home run for all students of the game." - Bill Musselman
- "Bob Kloppenburg and I were teammates at USC so I've followed his career closely- especially since both of us have been in the NBA for some time. Bob is considered by the people in the NBA as a "great" mind in basketball, and is especially respected for the defenses he has devised. I've studied his SOS Pressure Defense book and rate it as one of the top books on defense I have seen. His originality is thought provoking and every coach at all levels should have and study this book." - Fred "Tex" Winter, Asst. Coach for the Chicago Bulls.