"The Schoolboy" is about more than a child simply wishing he could be outside playing instead of at school, although this is part of the poem's meaning. The poet compares the children to caged birds, asking, "How can the bird that is born for joy / Sit in a cage and sing?" In the next stanza, the children are nipped flower buds, or "tender plants are stripped / Of their joy in the springing day, / By sorrow and care's dismay." In using these metaphors, the poet likens the growth of children to the natural return of birds and plants in the summer; education, then, becomes something more problematic than the thing that keeps children inside on a nice day. It is instead the source of the "sorrow and care's dismay" that "cages" the bird or blights the new blossoms—metaphorically speaking, education is the thing that prevents the "summer fruits" from appearing. In this sense, school is seen as not only unnatural, but also a threat to the natural order.

All of this is part of a larger metaphor, in which Blake compares the cycle of the seasons with the ages of man. Summer in this sense is a metaphor for youth, and the joys of youth (the "summer fruits") are something to be stored up against the "blasts of winter" (or "griefs") that come with adulthood.

In “The Schoolboy,” Blake compares a little boy forced to go to school to a caged bird as well as to a bud or blossom that has been nipped. The poem contrasts the life of a child who is free and happy in nature with that of a child forced to toil in a dreary schoolroom. If a boy is indeed a bird or a blossom, he will thrive only if he is allowed to fly free and drink in the sun’s rays.

 The poet expresses it this way:

How can the bird that is born for joy /Sit in a cage and sing? How can a child, when fears annoy, /But droop his tender wing …

 In the above stanza, the school boy is a bird, frightened by the schoolroom. Below he is a bud who will no thrive in the classroom:

 O father and mother if buds are nipped,/And blossoms blown away…

 This typically Romantic poem ends on a note of warning: the child deprived of his chance to run freely will not develop “summer fruits” and won’t have the resources to withstand the winter (the hard times in life). Blake depicts his imagined child as a pure and innocent creation who will be ruined, not improved, by the unnatural constraints of civilization. Nature, the narrator argues, is the best teacher of the young birds or buds.