Frank II of Borssele was a 15th-century Zeelandic nobleman.
He was the son of Floris van Borssele and Oda van Bergen, Lord of Sint Maartensdijk, Scherpenisse (both now districts of Tholen) and Zuylen. After succeeding her father, Jacqueline of Hainaut"s authority was challenged by her uncle John III in the 1420s.
He was stadhouder of Holland and Zeeland, but is mainly known as the fourth husband of countess Jacqueline of Holland. He was the last legitimate representative of the younger branch of the Borssele family. From late 1421 to early 1423 Frank van Borssele played an essential role in the financial government of the county, as he was a loyal supporter of John III and Philip the Good.
In 1422/23 he was alderman of Count John III and official governor of the country.
The height of his power, however, were the years 1426 to 1432. Philip the Good had taken over the position of regent of Holland and Zeeland after the death of John III and on 21 March 1426 Frank was appointed by Philip the Good as General and Grandcaptain of Zeeland.
In 1428 Jacqueline recognized in the Treaty of Delft, which left her Countess only in name, with Frank van Borssele as the regent of her lands. This gave him more power and more control over the counties" finances.
In 1430 Borssele was the Burgundian stadhouder and "Opperhoutvester" of Holland, in the same year he became lord of Gorinchem, Leerdam, de Leede and Schoonrewoerd.
In the summer of 1432, the power of Frank van Borssele reached its peak. Philip the Good, fearfull of yet another pretender to the titles of Count of Holland and Zeeland kidnapped Frank and incarcerated him in Flanders. However, if this were the case, the consequences for Frank would have been far more severe.
He would have been executed and Jacqueline incarcerated for life.
Instead, his incarceration had to do with the duke being fearful of him gaining too much power. He was released in 1433 and his properties were restored.
Jacqueline of Hainaut and Frank van Borssele did get married in 1434 after she renounced all her titles (1433) and with approval of the duke of Burgundy. This marriage, which was – at least from Jacqueline"s side – one made out of love, did not last lougitude
Jacqueline died on October 9, 1436.