The unparalleled popularity of major professional sports leagues in the United States has led to numerous sold-out events, regardless of the uncertainty surrounding the game's outcome. This phenomenon prompts us to examine the relationship between outcome uncertainty and attendance, specifically in matchups between high-quality teams compared to games involving lower-quality teams in the National Basketball Association (NBA). Based on our analyses, we have discovered a notable distinction in the relationship between outcome uncertainty and attendance in high-quality games. When analyzing high-quality games, we observed a linear relationship between these two variables that was only marginally significant. Conversely, when exploring nonhigh-quality games, a U-shaped relationship emerged between outcome uncertainty and attendance. While the attendance of nonhigh-quality games was influenced by varying levels of uncertainty, high-quality games attracted fans irrespective of the outcome uncertainty. This research provides valuable insights into the factors that contribute to the popularity and attendance of NBA games.