Nintendo Entertainment Analysis & Development Division, commonly abbreviated as Nintendo EAD and formerly known as Nintendo Research & Development No.4 Department (abbreviated as Nintendo R&D4), was the largest software development division within the Japanese video game company Nintendo. It was preceded by the Creative Department, a team of designers with backgrounds in art responsible for many different tasks, to which Shigeru Miyamoto and Takashi Tezuka originally belonged. Both served as managers of the EARD studios and were credited in every game developed by the division, with varying degrees of involvement. Nintendo EAD was best known for its work on games in the Donkey Kong, Mario, The Legend of Zelda, F-Zero, Star Fox, Animal Crossing, Pikmin, and Wii series.

Following a large company restructuring after the death of company president Satoru Iwata, the division merged with Nintendo's Software Planning & Development division in September 2015, becoming Nintendo Entertainment Planning & Development.

During the 1970s, when Nintendo was still predominantly a toy company, it decided to expand into interactive entertainment and the video game industry. Several designers were hired to work under the Creative Department, which, at the time, was the only game development department within Nintendo. Among these new designers were Makoto Kano, who went on to design various Game & Watch games, and Shigeru Miyamoto, who would create various Nintendo franchises. In 1972, the department was renamed to Research & Development Department; it had about 20 employees. The department was later consolidated into a division and separated into three groups, Nintendo R&D1, R&D2 and R&D3.

Circa 1983, Hiroshi Imanishi oversaw the creation of Research & Development No. 4 Department (commonly abbreviated to Nintendo R&D4), as a new development department dedicated to developing video games for home consoles, complementing the other three existing departments in the Nintendo Manufacturing Division. Imanishi appointed Hiroshi Ikeda, a former director at Toei Animation, as general manager of the newly created department, and Miyamoto as its chief producer. Also hired were Takashi Tezuka and Kenji Miki, graphic designers, Minoru Maeda, a designer, and Koji Kondo, Akito Nakatsuka, and Hirokazu Tanaka, all sound designers.

Ikeda's creative team had many ideas, but lacked the programming skills to put them into action. Mario Bros., one of the unit's first games, required assistance in this regard from Gunpei Yokoi and R&D1. Toshihiko Nakago was familiar with the chipset for the Family Computer, Nintendo's contemporary home console, as he was originally hired to work with Masayuki Uemura's Nintendo R&D2 to develop software development kits for Nintendo consoles. When R&D2 and Systems Research and Development, Nakago's company, began porting R&D1-developed arcade games to the Famicom, Shigeru Miyamoto lured him and SRD to R&D4 to help develop Excitebike.

Following the release of Excitebike, R&D4 developed a Famicom port of the beat 'em up arcade game Kung-Fu Master, called Spartan X in Japan and Kung Fu everywhere else. The game improved on features introduced in Donkey Kong, representing a key step in the life of the platform game genre. Their next game was Super Mario Bros., a self-developed sequel to Mario Bros. The game standardized many aspects of the platform genre, and went on to be a critical and commercial success. Developed concurrently, but released a year later, was The Legend of Zelda, an action adventure game. The phenomenal sales of Mario and Zelda made Miyamoto a household name, and allowed the department to expand. Hideki Konno, Katsuya Eguchi, Kensuke Tanabe, and Takao Shimizu were all hired at this time, and they would become producers themselves.

In 1989, one year before the Super Famicom was released in Japan, the R&D4 department was spun-off and made its own division named Nintendo Entertainment Analysis & Development (commonly abbreviated as Nintendo EAD). The division was comprised into two departments: the Software Development Department, which focused on video game development and was led by Miyamoto, and the Technology Development Department, which focused on programming and developing tools and was led by Takao Sawano. The technology department relied on R&D2 engineers who assisted SRD with software libraries. Following the release of F-Zero, the first video game fully programmed by EAD, they collaborated with Argonaut Software to develop the Super FX, a chip which, when placed in Super Famicom cartridges, enabled the use of 3D graphics. As 3D gaming became more prominent, so, too, did the department, programming several of Nintendo EAD's 3D games with SRD.

In 1997, Miyamoto explained that about twenty to thirty employees were devoted to each Nintendo EAD title during the course of its development, and that SRD was a company within the division, formally Nintendo R&D2's software unit, and was composed of about 200 programmers.