The primary themes of Doctor Faustus are the relationship between knowledge and power and the consequences of attempting to attain knowledge beyond a certain extent. The play's protagonist, Doctor John Faustus, is an accomplished, esteemed scholar who is well-versed in a variety of academic fields, which he believes he has already mastered. At the beginning of the play, Doctor Faustus dismisses several areas of study by deeming philosophy "odious and obscure," mentioning that law and physics are "for petty wits" and commenting that divinity is "the basest of the three." Doctor Faustus turns his focus toward the metaphysics of magicians and the study of necromantic books to attain forbidden knowledge, which he finds intriguing and rewarding.

Doctor Faustus's motivation to practice necromancy is driven by his pride and desire to attain limitless knowledge, which he believes will bring him authority, prestige, and wealth. Doctor Faustus associates knowledge with power and seeks to know "the secrets of all foreign kings" as well as the unknown elements of the universe, which he will use to attain absolute power. The Bad Angel confirms the nature of Faustus's dangerous quest and tempts him to begin exploring necromancy, which he describes as "that famous art / Wherein all Nature’s treasure is contain’d."

While Faustus's relationship with Mephistopheles does allow him to obtain firsthand knowledge of astronomy, he is unable to unlock all the secrets of the universe, which are under God's control and out of reach. Although Faustus's desire for knowledge is not inherently bad, he fails to recognize that proper knowledge and education have their limits, and his decision to seek too much leads to his demise. At the end of the play, the Chorus reiterates the moral of the story by instructing the audience to only "wonder at unlawful things" and refrain from practicing more than "heavenly power permits."

A major theme of the play that is it is short-sighted to make a pact to sell your soul to the devil in return for a few decades of worldly pleasure. In his pride, Faustus thinks he knows what he is doing, but, as the play makes clear, he does not.

As the play shows, it is not just that Faustus will spend eternity after he dies at the mercy of the devil in hell—though that is something to fear—but that everything the devil offers him on earth leaves him ultimately empty and unfulfilled: the joys he thinks worldly success, pleasure, and sex will bring him do not live up to his expectations. None of what he gets is really that much fun and certainly not worth the price.

Faustus is also short-sighted and filled with pride in his conviction that once he has sold his soul, it is impossible to repent and come back to God. Faustus, because his understanding of Christian theology is so poor, assigns too much power to the devil he worships and not enough to the God who can save him. If he had humbled himself to admit he had made a mistake and repent of his sin, he could have bested Satan and achieved salvation—but that humbling is beyond him until too late.

The character of Doctor Faustus represents the key theme of hubris, or overweening pride. Faustus is deeply unsatisfied with his life, despite his remarkable intellectual gifts. He wants to be famous; he wants to have renown; he wants to be known the world over for extraordinary feats of magic that will improve the lot of humanity; he wants to be feted wherever he goes as a towering genius.

Faustus's pride makes him easy prey for Mephistophilis and his devious wiles. He offers Faustus all he's ever wanted in return for his soul. As Faustus is in the constant grip of hubris, he gladly signs up to this dangerous bargain. Although Faustus subsequently displays a profound sense of unease at the deal that he's made, his pride holds him back from repenting. But then all the time he's been exercising his remarkable powers, he's effectively been playing God, and God does not repent.

A major theme of the play is the sin of excessive ambition. Faustus, a clever scholar, wants too much; he seeks to gain knowledge and power beyond normal human limits. In the end, he cannot be allowed to do this; although he enjoys a brief ascendancy, he is ultimately consigned to hell and everlasting punishment, literally dragged offstage by devils. His final words, at the end of a long and despairing soliloquy, rise to sheer agony:

My God, my god, look not so fierce on me!

Adders and serpents, let me breath awhile!

Ugly hell, gape not! Come not, Lucifer!

I’ll burn my books!

Faustus thus vainly entreats the dark powers not to claim him, and attempts to renounce his sin – 'I’ll burn my books!' It was his overweening desire for knowledge that has brought him to this pitiable and tragic end. Now he repents of it – but only when it is far too late. He has to pay for daring 'to practise more than heavenly power permits,' as the Chorus solemnly pronounces in the very last lines of the play.

In his vaunting ambition, Faustus resembles other Marlovian protagonists such as Tamburlaine, the historical conqueror who built a great empire, and Barnabas, the title figure of The Jew of Malta, who aspires to unlimited wealth.