Our Town opens at dawn with the birth of twins in a Polish village and concludes at night with the death of Emily Webb Gibbs during childbirth. As one life ends, another begins. Throughout the play, Wilder, through the character of the Stage Manager (a role Wilder himself once played), emphasizes the perpetual cycle of life. In his opening monologue, he points out that the names on the gravestones from the 1600s are "the same names that are around here now." At the beginning of Act Two, the Stage Manager talks about the sun rising "over a thousand times," the growth and decline of some townsfolk, and the millions of gallons of water that have flowed past the mill. His thoughts on marriage are particularly thought-provoking:

I've married over two hundred couples in my time. Do I believe in it? I don't know. M marries N... millions of them. The cottage, the g-cart, the Sunday-afternoon drives in the Ford, the first rheumatism, the grandchildren, the second rheumatism, the deathbed, the reading of the will... Once in a thousand times, it's interesting.

Thornton Wilder is often considered a spiritual writer, and Our Town is frequently interpreted as a spiritual play. Yet, the play rarely mentions concepts like heaven, God, or other traditional religious themes. At the beginning of Act Three, the Stage Manager contemplates the idea of eternity.

There are certain things we all inherently know, but we rarely examine them closely. We all understand that something is eternal. It's not houses, it's not names, it's not the earth, and it's not even the stars... deep down, everyone knows that something eternal is connected to human beings. For five thousand years, the greatest minds have been imparting this to us, and still, you'd be surprised at how people often lose sight of it. There's something profoundly eternal within every human being.

In Our Town, love is a central theme, and Wilder presents many examples to the audience. The primary characters exhibit deep affection for each other, and the play showcases different forms of love. In Act One, familial love and friendship take center stage. Parents and children express care for one another, and neighbors demonstrate their affection too. In Act Two, romantic love blossoms into marriage. Act Three illustrates spiritual, selfless love—love that asks for nothing in return.