Adelaide (Aleidis) of Holland Countess of Holland  24
- Born: c .?1230
- Marriage: John of Avesnes Count of Hainaut  on 9 Oct 1246
- Died: 1284, Valenciennes, , Nord-Pas-de-Calais, France at age 54
- Buried: 9 Apr 1284
Noted events in her life were:
• Acceded: regent of Holland, 1258. Between 1258 and 1263, Adelaide was regent of Holland in the name of her nephew Floris V. She called herself Guardian of Holland and Zeeland (Tutrix de Hollandie et Zeelandie). After he came of age, she continued to advise him.
Adelaide married John of Avesnes Count of Hainaut  [MRIN: 5146], son of Burchard of Avesnes d'Avesnes  and Margaret II of Constantinople Countess of Flanders , on 9 Oct 1246. (John of Avesnes Count of Hainaut  died on 24 Dec 1257.)