Lagemann is a German surname and can refer to the following people:

• Ramana Lagemann, an American rally car driver
• Rainer Lagemann, a German metal sculptor and photographer
• Hanns Hermann Lagemann (1924–2003), a German politician (CDU), member of the Landtag of North Rhine-Westphalia
• Inge Lagemann (1944–2014), a German politician (SPD), member of the Landtag of North Rhine-Westphalia
• Johann Jakob Lagemann (1696–1766), a German gunsmith famous for making breech-loading wheellock sporting rifles in Vollmarshausen, Germany
• Sigrid Lagemann (1924–1992), a German actress and voice actress

• Alexander Grechaninov
• Alexander 'Greek' Thompson
• Alexander 'Greek' Thomson
• Alexander Gregory Barmine
• Alexander Gretchaninov
• Alexander Griboedov
• Alexander Griboyedov
• Alexander Grigor Harut‘yunyan
• Alexander Grigori Arutyunyan
• Alexander Grin
• Alexander Grinevsky
• Alexander Grischuck
• Alexander Grischuk
• Alexander Gromov
• Alexander Grothendieck
• Alexander Gus Spanos
• Alexander Haig
• Alexander Hale Smith
• Alexander Hamilton
• Alexander Hamilton, 10th Duke of Hamilton
• Alexander Hamilton High School (Los Angeles)
• Alexander Hamilton International Airport
• Alexander Hamilton Stephens
• Alexander Hamilton US Custom House
• Alexander Hamilton U.S. Custom House