 Sir Theobald de Grenville II (c. 1343 – July 1381) (son), who married by 1365, Margaret Courtenay (born between 1342 and 1350, died after July 1381), a daughter of Sir Hugh Courtenay, 2nd Earl of Devon (12 July 1303 – 2 May 1377), and his wife, Margaret de Bohun (b.3 April 1311 - d. 16 December 1391), daughter of Humphrey de Bohun, 4th Earl of Hereford (by his wife Elizabeth of Rhuddlan, a daughter of King Edward I)

Sir John Grenville (died 1412) (eldest son and heir), Sheriff of Devon in 1395, Sheriff of Cornwall in 1411 and four times MP for Devon, in 1388, 1394, 1397 and 1402.At some time before September 1391 he married Margaret Burghersh (c. 1376 – c. 1421), elder daughter and co-heiress of Sir John Burghersh, MP, of Ewelme, Oxfordshire.