An English place-style name likely meaning great clearing or settlement meadow from Old English elements.
Grantley is an English surname of Norman and Old English origin that carries the particular combination of aristocratic weight and pastoral imagery typical of English place-names. It derives most likely from the village of Grantley in North Yorkshire, where the place-name itself combines Old English elements suggesting "the great wood" or "the great clearing" — gran (great, or possibly a personal name) plus leah (a woodland clearing, grove, or meadow), one of the most common suffixes in English place-name formation. The surname was carried by various Yorkshire gentry families before beginning its slow migration into given-name use.
The name's most prominent historical bearer is Richard Grantley Norton (created 1st Baron Grantley in 1782), a British barrister and politician whose title kept the name alive in aristocratic consciousness through the nineteenth century. The -ley suffix puts Grantley in company with a large family of English names — Bradley, Hartley, Barclay, Brantley — that have made comfortable transitions from surnames to given names, particularly in the American South and in communities with strong British heritage pride. Its closest contemporary relative, Brantley, achieved mainstream American popularity in the 2010s, partly through country music.
Grantley sits at an interesting point in the naming landscape: more formal and less common than the very popular Brantley or Grant, but clearly in the same tonal family — outdoorsy, traditionally masculine, rooted in English land and law. For parents who find Grant too short or Brantley too trendy, Grantley offers a similar register with more rarity and a slightly more imposing presence. It sounds like a name from a Victorian novel — the trustworthy barrister, the Northamptonshire landowner — repurposed for the twenty-first century.