The serial number "55402MS" can be found on crate carousels in Mario Kart 8's Sunshine Airport. This code actually references the European and Australian release date for Super Mario Sunshine, which was October 4th, 2002.

On the Wii U box art, Mario and Peach are going in the opposite direction of the other racers on the game's box art. This may be an oversight by the developers, but it's also possible that the box art is showing the game's battle mode.

On the retro track Mario Circuit, the raised hairpin turn is supported by the Ultra Arm. This is a reference to the Ultra Hand, a toy made by Nintendo in 1966 by former employee Gunpei Yokoi.

In the track "Sunshine Airport", the names of other tracks are listed as flight destinations.

Instead of using the antigravity mechanic in Mario Kart 8, the team originally planned to have drills on the karts so players could travel through the earth.

In Mario Kart 8's Bone Dry Dunes level, near the finish line there are tapestries on the side of the road showing a pattern of the Angry Sun from Super Mario Bros. 3.

A year after the release of Mario Kart 8, a hip-hop dance known as the "dab" would gain prominence in mainstream culture, becoming a popular internet meme. Mario fans later noticed that at certain angles, one of Donkey Kong's Jump Boost animations in Mario Kart 8 coincidentally resembled a dab, with Donkey Kong holding his head down and stretching out one of his arms, but keeping his other hand close to his head. In Mario Kart World, this animation returns in a different context. While Donkey Kong now faces his head forwards while doing the animation, straying away from dabbing, he also stretches out both arms, making the similarity to dabbing more prominent overall.