Leader Tower, Modern skyscraper in Saint Petersburg, Russia

Leader Tower is a 42-storey skyscraper at Constitution Square in the Moskovsky district of southern St. Petersburg. Its height, according to the developer, is 145.5 m, with ground floors of 4.5 m and typical floors of 3.4 m. The building houses a Class A business centre of 52,700 m² and has a five-level underground car park for 250 cars.

Construction began in February 2009 under the design of Remark LLC, but work stopped at foundation level in May 2009 and resumed nine months later, in February 2010. In 2010 the Committee for Urban Planning and Architecture revoked the building permit, arguing the tower would spoil views from St. Isaac's Cathedral; the developer successfully challenged the decision in arbitration court. The frame was topped out in June 2012 and the building was completed in 2013.

The tower stands on Constitution Square in the Moskovsky district, which gave it the nickname Constitution Tower. Its LED media facade of 5,040 tubes runs over 16,500 metres, and in 2017 a court rejected the city press committee's demand to dismantle it. The building appears as the YouTube office in TheBrianMaps' short film "The Last Button 2".

The building is an office center, not a public observation deck, so there is no visitor access to upper floors. It stands at Constitution Square in the Moskovsky district, where the glowing media facade is best seen after dark from the surrounding open space.

The media facade uses 5,040 LED tubes with a combined length of more than 16,500 metres, set into the facade at one-metre intervals. In 2017 the city's press committee sued to have it removed, but lost because it could not prove the screen showed advertising only; the owner later agreed to keep commercial content to 30% of broadcast time.