Love
Anne has three suitors, two of whom she feels no love for whatsoever, and one of whom she is in love with. Her parents each have a favored suitor whom they are shamelessly promoting, and with whom they scheme to trick her into elopement and marriage, against her wishes. Anne has other ideas and by the end of the play it becomes clear that she has taken matters into her own hands and married the man she is in love with. This climax is also seen as a "teachable moment" for the rest of the characters who have all been pursuing romance with less genuine and more transactional motives.
Comic Philandering
Falstaff's reason for being seems to be to misappropriate other people's wives and he does not seem to mind everyone knowing this. He is even perfectly happy when the wives find out about his intentions, and when they discover that he has made the same offer of romance to all of them. The fact that these women are married certainly does not deter him - in fact, quite the contrary. He seems to enjoy the game, the subterfuge, and the challenge. However, it is important to note that Falstaff does not necessarily succeed in any of his attempts to seduce the wives. Part of his comic character, therefore, lies in the disparity between his pursuits and his accomplishments. These are the same qualities that drew audiences to him for his roles in the Henriad, where he often provided comic relief as a boisterous and boastful knight who was also comically large and perpetually drunk.
Deception
There is a great deal of deception in this play. In fact, all of the characters are deceiving others at some point. The greatest deception is amongst the wives, who band together to deceive Falstaff in order to teach him a lesson. Even Anne is involved in a deception as she outwits her parents and deceives them so that she can marry her sweetheart. Her parents have already proved themselves master (and mistress) of deception by planning Anne's elopement. The deception theme also incorporates the signature Elizabethan "men dressed as women" theatrical convention, this time involving Falstaff dressing as the fat old aunt. Deception is really the theme around which the entire plot of the play is constructed.
Gender
The Merry Wives of Windsor indulges the strength of women specifically when it comes to outwitting men. On finding that Falstaff is trying to seduce each of them in order to get hold of their husband's money, the wives work together to come up with a plan to both teach him a lesson and humiliate him publicly. An added benefit of the plan is that it also teaches the husbands not to be so jealous. The plans are very successful and achieve the ladies' goal. Anne also proves herself to be a powerful woman when she outwits her parents and marries the person she has chosen for herself and not the person they have each chosen for her. The women in this play are far more intelligent than the male characters are, which contributes to the play's comic nature.
Communication
Despite the fact that the plays of the Henriad (where Falstaff first appeared) are history plays and The Merry Wives of Windsor is a comedy, Shakespeare carries more than just Falstaff from one world to the other. Indeed, The Merry Wives of Windsor appears equally invested in the notion of language and communication as plays like Henry V, known for its incorporation of multiple languages besides English. However, whereas the linguistic richness of Henry V serves to underscore diversity in England, the focus on language in The Merry Wives of Windsor is deployed for comic purposes. Characters frequently make fun of Evans and Caius for their Welsh and French accents, emphasizing their otherness as a source of entertainment rather than as a reflection of a diverse kingdom.
Jealousy
Of course, along with the themes of deception and gender comes the theme of jealousy. The husbands of the Windsor wives invite their own destruction when they let their jealousy overtake them. It clouds their minds so that they cannot see things as they truly are (i.e., they cannot perceive that Falstaff is himself being fooled by the women). The play suggests that this jealousy stems from a fundamental mistrust of women that was not uncommon in early modern England. Indeed, one of the primary anxieties among noblemen at the time was that they would become fathers to illegitimate children. Through its comic plots, the play subtly criticizes this misogynistic perspective and allows the women of the play to showcase their strengths.
Social Class
The Merry Wives of Windsor stands out among Shakespeare's plays as one of the only performances to feature a representation of the English middle class. The play is fundamentally anachronistic – it is allegedly set during Falstaff's lifetime and thus during the reigns of Henry IV and Henry V, but by all accounts appears to take place during what would have been, at the time, contemporary Renaissance England. As such, it showcases the daily lives of what was then the emerging English middle class. Neither nobles nor laborers, the middle class was largely made up of merchants and businessmen who had taken advantage of increased trade.