Scholars have noted that despite the story's light-hearted nature, reflected in Tolkien's playful use of his professional discipline, philology, it embodies several serious concerns.

The story parodies multiple aspects of traditional dragon-slaying tales, and has roots in modern and medieval literature, from Norse myth to Spenser's The Faerie Queene.

Its concern for the "Little Kingdom" embodies Tolkien's environmentalism, in particular his well-founded fears for the loss of the countryside of Oxfordshire and surrounding areas.

The giant, on returning home, relates to his friends that there are no more knights in the Middle Kingdom, just stinging flies—actually the scrap metal shot from the blunderbuss—and this entices a dragon from Venedotia, Chrysophylax Dives, to investigate the area.

The Tolkien scholar John Garth comments that the tale is "an elaborate false explanation for the name of the Buckinghamshire village of Worminghall".

[10] Another joke puts a question concerning the definition of blunderbuss to "the four wise clerks of Oxenford": "A short gun with a large bore firing many balls or slugs, and capable of doing execution [killing people] within a limited range without exact aim.

)"[11] Tolkien had worked on the Oxford English Dictionary, and the "four wise clerks" are "undoubtedly" the four lexicographers Henry Bradley, William Craigie, James Murray, and Charles Talbut Onions.

"[13] Romuald Lakowski describes Farmer Giles of Ham as a "delightful, and even in places brilliant, parody of the traditional dragon-slaying tale.

[14] Alex Lewis, in Mallorn, writes that Tolkien lamented the loss of the countryside in and around Oxfordshire, which formed "the Little Kingdom" of the story.

Tolkien loved nature, especially trees, and had what Lewis calls "well-founded" fears for the environment, "verg[ing] on the prophetic".

[16] Lewis states that Tolkien had hoped to write a sequel to Farmer Giles of Ham, but found that his legendarium had "bubbled up, infiltrated, and probably spoiled everything", and that it was "difficult [in 1949] to recapture the spirit of the former days, when we used to beat the bounds of the L[ittle] K[ingdom] in an ancient car.

"[16] Tolkien was horrified by the change that motor traffic wreaked on Oxford, and the air pollution; he had given up his happy but dangerous driving, as depicted in his children's story Mr. Bliss, at the start of the war.