Gertrude or Gertrud may refer to:
- The "underwater phone" used by submarines for communication
- Gertrude (Hamlet), Hamlet's mother
- Gertrud (novel), by Hermann Hesse
- Gertrud (play), by Hjalmar Söderberg
- Gertrud (film), 1964 Danish film based on Söderberg's play
- Gertrude (Code name), invasion plan for Turkey by Nazi Germany
- Gertrude (crater), crater on Uranus' moon Titania
- 710 Gertrud, minor planet
Places named Gertrude:
- Gertrude, Arkansas
- Gertrude, California
- Gertrude, West Virginia
People with Gertrude as the full name:
- Gertrude of Aldenberg (1227–1297), blessed in the Roman Catholic Church
- Gertrude of Austria (1226–1288)
- Gertrude of Babenberg (d. 1150), Duchess of Bohemia
- Gertrude of Bavaria (d. 1197), Queen of Denmark
- Gertrude of Brunswick (d. 1117), Markgräfin of Meissen
- Gertrude of Dagsburg (d. 1225), Duchess of Lorraine
- Gertrude of Hackeborn (1223–1292), Abbess of Hellfta
- Gertrude of Hohenburg (d. 1281), Queen of the Romans
- Gertrude of Merania (1185–1213)
- Gertrude of Nivelles (626–659)
- Gertrude of Poland
- Gertrude of Saxony (d. 1113), Regent of Holland
- Gertrude of Süpplingenburg, Duchess of Bavaria and Saxony
- Princess Gertrude, daughter of Henry the Lion
- Gertrude the Great (1256–1301) known informally as Saint Gertrude
- Saint Gertrude, also known as Gertrude of Hamage, founder of the convent Hamage near Douai—see Chronological list of saints and blesseds: 7
- Gertrude of Holland, wife of Robert I, Count of Flanders
People with the given name Gertrude:
- Gertrude (given name)