The significance of the title of O’Henry’s “After Twenty Years” is great. Taken literally, the title reflects that the action of the story takes place after twenty years of time have elapsed. However, the title also reflects a theme and irony of the story.

The theme that true friendship spans time, even decades, is clear. Jimmy and Bob are old friends. At some point, twenty years ago, they agreed they would meet at this place and time. It’s clear that they were good friends. Bob reminisces about Jimmy, “the truest, stanchest old chap in the world,” and is excited to meet his old buddy. Even though the friends have not directly communicated with each other over time, their bond remains strong so that both men keep their appointment to reunite after twenty years.

Additionally, the friendship is still so strong that Jimmy cannot arrest his old friend when he recognizes Bob as a wanted criminal. Jimmy took an oath as a police officer to uphold the law; he will not turn his back on that oath, but he also cannot face his friend as he arrests him. So, he asks another officer to arrest Bob. Jimmy finds a way to uphold his oath and morals, even if that means placing his friend in jail—he remains the loyal and true person that Bob remembers him being.

It is ironic that the two old friends end up on opposite sides of the law. It’s to be presumed that friends have things in common—goals, ideals, morals. Yet, Bob becomes a criminal while Jimmy becomes a lawman. Although they were raised together “just like two brothers,” they part ways in morality. Perhaps circumstances are responsible for Bob’s change, since he traveled a lot in his search for success in the West and had to compete with “some of the sharpest wits.”

Jimmy, on the other hand, remained in New York where he had grown up, so he might not have had to struggle as much as Bob did. When Bob recognizes that the tall officer is not Jimmy, he says that twenty years is a long time—but not long enough to change someone’s facial features. The officer responds that twenty years “sometimes changes a good man into a bad one.”

The story "After Twenty Years" tells the tale of two friends who have been separated for a long time. When they were younger, the two friends had to go their separate ways as Bob attempted to make a fortune for himself in the West. In their pact, they decided to meet up "after twenty years" at the hardware store as a predetermined location.

The title also belies the changes in life that take place over a long period of time. The two friends were similar in their old lives, but after some misfortune, Bob has become a notorious criminal, while Jimmy has turned into a well regarded police officer. The divergence of their lives highlights the difference that occurs in people after twenty years of life.

The title,"After Twenty Years," is at the heart of O. Henry's narrative.  For, two old friends who separated in their youth have agreed to meet each other in front of their favorite restaurant. When the policeman asks the man standing in this doorway why he is there, he states,

"Twenty years ago to-night...I dined here at 'Big Joe' Brady's with Jimmy Wells, my best chum.... He and I were raised here in New York, just like two brothers....The next morning I was to start for the West to make my fortune.  You couldn't have dragged Jimmy out of New York....Well, we agreed that night that we would meet here again exactly twenty years that date and time, no matter...what distance we might have to come.

It is the meeting of the two old friends after twenty years that causes the conflict of the story because Jimmy Wells is now a policeman while Bob has become 'Silky Bob,' a criminal who is wanted in Chicago. When Bob strikes a match, Patrolman Wells recognizes his old friend and realizes he is a wanted criminal.  But, "after twenty years," he does not have the heart to arrest his old friend; consequently, he sends an undercover man to arrest his own friend who stands waiting in the doorway of the former restaurant; this undercover policeman carries a letter from an old friend explaining why he could not meet his old friend Bob.

Twenty years is a long time.  It is long enough for people who were once young to become middle aged.  In this story, two friends were basically still teenagers when they went their separate ways.  They had not formed their life paths yet.

He and I were raised here in New York, just like two brothers, together. I was eighteen and Jimmy was twenty.

Bob clearly wanted to be rich.  He tells the “cop” he meets on the street while waiting that he went west to make his fortune.  The fact that Bob left and Jimmy stayed tells you about both of their personalities.  Bob was ambitious, and wanted to be rich.  He’s the one that left.  Jimmy, on the other hand, was satisfied with who he was.  He stayed.

It is not surprising really that Bob became a criminal while Jimmy became a cop.  Jimmy is an honorable man though, and he has to ask another cop to arrest Bob for him because he doesn’t have the heart to arrest his old friend himself.

[Twenty years] sometimes changes a good man into a bad one…

The cop that arrests Bob, who has been impersonating Jimmy, tells Bob this.  Going west is no coincidence.  Throughout America’s history, the west has always been a place of opportunity.  However, there has often been illegal activity there too.  Bob went west to make his fortune by breaking the law, and Jimmy stayed behind and became the law.