NOS Alive (formerly Optimus Alive! and Optimus Alive) is an annual music and arts festival held in the Algés riverside, close to Lisbon, in Portugal. It takes place during the second week of July and lasts 3 or 4 days. It currently has six stages, including a stage dedicated to fado music and a stage dedicated to stand-up comedy.

The Alive festival was created by the live entertainment company Everything is New in 2007. The name of the festival is taken from the Pearl Jam song “Alive”. The first edition occurred between 8th and 10th June 2007, under the name “Oeiras Alive!” and had two stages. The headliners were Pearl Jam, The Smashing Pumpkins and the Beastie Boys.

In its second edition, the date of the festival was changed to the second weekend of July and the name of the festival was changed to include a naming sponsor. Between 2008 and 2010, the festival was named “Optimus Alive!”, after the telecommunications company Optimus. A third stage was added in the 2009 edition. The 2009 edition was also the only edition to date to have a day dedicated to heavy metal music in the main stage, which had Metallica as the headliner.

In 2011, the exclamation mark was dropped from the festival name and it became “Optimus Alive” until 2014. To mark its 5th anniversary, an extra day was added to the festival, making it a 4-day event in 2011. A new bandstand stage was added in 2012. In 2014 the naming sponsor company Optimus changed its name to NOS, and the festival name was changed accordingly to NOS Alive in 2015.

A stage dedicated to stand-up comedy was also added in the 2014 edition. In 2016, a new stage dedicated to fado music was added.