Andrea Albert Pierre Casiraghi (born 8 June 1984) is the elder son of Caroline, Princess of Hanover, and her second husband Stefano Casiraghi. He is the eldest grandchild of Rainier III, Prince of Monaco, and American actress Grace Kelly. Casiraghi is currently fourth in the line of succession to the Monegasque throne, following his twin cousins and mother.

Casiraghi was born on 8 June 1984 at the Princess Grace Hospital Centre in La Colle, Monaco, to Princess Caroline of Monaco and her husband, the Italian businessman and athlete Stefano Casiraghi.
The eldest grandchild of Rainier III, Prince of Monaco, and his wife, former American actress Grace Kelly, Casiraghi was named after his father’s childhood friend, his maternal uncle Prince Albert and his maternal great-grandfather Prince Pierre, Duke of Valentinois. Casiraghi’s godparents are his maternal aunt Princess Stéphanie and his paternal uncle, Marco Casiraghi. His sister Charlotte was born on 3 August 1986, and his brother Pierre on 5 September 1987.
On 3 October 1990, Casiraghi’s father died in a speedboat accident in Monaco. He was buried several days later in Monaco’s Chapel of Peace. Princess Caroline did not know how to tell her children that their father had died, so her father, Prince Rainier, did so. Andrea reportedly suffered nightmares and insomnia after his father’s death. To protect her children from excessive media attention, Caroline moved to Saint-Rémy-de-Provence, and later to Paris.
In 1999, his mother married Ernst August, Prince of Hanover, and gave birth to Princess Alexandra of Hanover. Along with a half-sister, Casiraghi gained two stepbrothers, Ernst August, Hereditary Prince of Hanover, and Prince Christian of Hanover.

Growing up mostly in France, Casiraghi earned his international baccalaureate from the International School of Paris in December 2002. Following a period at McGill University in Montreal, Quebec, Canada, he eventually graduated in 2006 with a B.A. degree in visual arts and international politics from the American University of Paris. From 2007 to 2009, Casiraghi studied at The New School in New York City, receiving his M.A. degree in international affairs, and then did an internship at the embassy of Qatar in France. In 2014, he started a Master of Business Administration at IE Business School (formerly known as Instituto de Empresa) in Madrid.

Since 2004, Casiraghi has been involved, to varying degrees, with the World Association of Children’s Friends (AMADE), a philanthropic organization founded in 1963 by his grandmother Grace; it is now presided over by his mother Princess Caroline. He spent eight months teaching children in Senegal, Togo, and Niger. In August 2006, Casiraghi took his involvement deeper and paid a very serious visit to Manila on behalf of a joint venture of AMADE and the Virlanie Foundation. Since 2007, he has been the patron of the Motrice Foundation, which funds research into cerebral palsy. Casiraghi sponsored the Hospices de Beaune charity auction that was held in November 2009.
Casiraghi regularly attends important social events in Monaco related to the Monegasque Princely Family, such as National Day, the Rose Ball, and the Formula One competition Monaco Grand Prix. In 2011, Casiraghi and his siblings Charlotte and Pierre hosted Monaco’s annual Rose Ball, in the absence of Prince Albert, Princess Caroline and Princess Stéphanie who were mourning the sudden death of their aunt Princess Antoinette, Baroness of Massy, a few days earlier. Casiraghi gave the speech at the start of the event. The same year, he attended the wedding of his uncle Prince Albert and Charlene Wittstock, which took place on 1 and 2 July 2011.

In July 2012, Princess Caroline released a statement announcing that her son Andrea Casiraghi and Tatiana Santo Domingo became engaged after a seven–year relationship. Prior to their wedding, she had already accompanied Casiraghi at some of most important social events in Monaco, such as the Rose Ball, the enthronement of Prince Albert II, the Monaco Grand Prix and the wedding of Prince Albert and Charlene Wittstock.
On 6 November 2012, his fiancée Tatiana Santo Domingo announced to La Voz Libre that she was expecting a baby. She gave birth to a boy, a son named Alexandre Andrea Stefano “Sacha” Casiraghi, on 21 March 2013 ,at Portland Hospital in London, England. As his parents were not married at the time of birth, he was not then included in the Monegasque line of succession. However, due to their subsequent marriage their son currently occupies the fifth position in the line of succession to the Monegasque throne.
Casiraghi and Santo Domingo were married in a civil ceremony in the Princely Palace of Monaco on 31 August 2013. A religious ceremony was later held in Gstaad, Switzerland, on 1 February 2014. Their second child, a daughter named India, was born in London on 12 April 2015.
Casiraghi is fluent in French, Italian, English and German as well. His hobbies and interests include reading, football, horse riding, water sports, skiing and collecting Swatch watches.