Alberto Castellani (Perugia, 15 November 1948) is an Italian tennis coach.

In 1983 he directed the Federal Tennis Training School of Cianciano Terme (Siena) and began training high-level players.

In 40 years of activity as a professional tennis coach, he has trained 24 players ranked in the top 100 in the world, including Rainer Schuettler (ATP No. 5), Janko Tipsarevic (ATP No. 8), Marc Rosset (ATP No. 9), Ivo Karlovic (ATP No. 14), Hicham Arazi (ATP No. 22), Damir Dzumhur (ATP No. 23), Karim Alami (ATP No. 25), Laslo Djere (ATP No. 27), Pablo Arraya (ATP No. 29), Tom Van Houdt (ATP No. 36), Adrian Voinea (ATP No. 36), Jean-Philippe Fleurian (ATP No. 37), Irakli Labadze (ATP No. 42), Oliver Marach (ATP No. 82 in singles and No. 2 in doubles) and Italian players Omar Camporese (ATP No. 18), Francesco Cancellotti (ATP No. 21 ATP), Diego Nargiso (no.67 ATP) and Claudio Pistolesi (no.71 ATP).

In 1998, he took part, as coach of the Moroccan Davis Cup national team, in two Davis Cup matches of the International World Group: the first played in Casablanca between Morocco and England, and the second between Morocco and Argentina in Agadir (Morocco). Subsequently, in 2011, he returned to be coach of Morocco for the Davis Cup match between Morocco and Bosnia played in Marrakech.

In the late 90s, for short periods, he trained Novak Đoković in Perugia and Bettona.

During his nearly 40 years of activity as a professional tennis coach, he has taken part in more than 300 ATP events, Challenger tournaments, Grand Slams, Masters 1000 and Super 9.

On August 28, 2010 in New York, Alberto Castellani founded the GPTCA (Global Professional Tennis Coach Association) together with 49 top tennis coaches in the world including Toni Nadal, Dirk Hordorff, Rainer Schuettler, Larry Passos, Jose Perlas, Boris Sobkin and Marc Gorriz. In just two years, the GPTCA achieved recognition by the ATP and became the only association in the world certified by ATP Tennis.

From the 90s to today he has published three books:

“Mental Preparation in Tennis” published by Editori del Grifo (Siena, Italy), “Tennis Training” published by Società Stampa Sportiva, “Easy Tennis: Let’s Play Tennis” published by Calzetti e Mariucci (Perugia, Italy). He then collaborated for more than 10 years with the most popular tennis magazine in Italy, "Il Tennis Italiano".

Thanks to his successes over the years and with many different players, in 2019 he is among the three candidates for the ATP Award Coach for the lifetime achievement award, where he placed second behind Tony Roche and ahead of Niki Pilic, and first among the "former non- professional players".