Georges Iscovescu (Boyer) is a Romanian dancer, but really a gigolo. Georges used to make a good living romancing the rich ladies of the European jet set, but when a little thing called World War II brought an end to that, Georges emigrated to the Americas. He finds himself stuck in a Mexican border town, unable to enter the United States for at least five years due to a very limited quota for Romanians, with no prospects, running up debt.
Enter Anita (Goddard), Georges's old dance partner from the European circuit, who has made a new life for herself as a gold digger. Anita, who is Australian, reveals to Georges that she gained entry into the United States by marrying a gullible American, whom she dumped as soon as she got a green card. She suggests that he do the same, and that the two of them can start a new life together after Georges gains entry to the USA and dumps his wife. Georges sets out to find a mark among the American tourists in the town and eventually meets Emmy Brown (de Havilland), a naive schoolteacher.
Getting Emmy to marry him is quick work for Georges. Unsurprisingly, while sitting out his four-week wait he falls in love for real with the beautiful, good-hearted Emmy. Also unsurprisingly, Anita is unwilling to be dumped.
Hold Back the Dawn netted de Havilland her second Oscar nomination; she lost Best Actress to her sister Joan Fontaine for Suspicion. This was the last film Billy Wilder ever wrote but did not direct. Conflicts with Mitchell Leisen over script decisions led Wilder to decide he needed to direct his own scripts.
- An Immigrant's Tale: Not just Georges but other immigrants in limbo at the Hotel Esperanza, like a French barber as well as a German writer and his family. Mrs. Kurtz is determined that her baby will be born an American. When she goes into labor before the papers have come, she staggers across the border into Inspector Hammock's office, and has the baby there.
- The Cameo: Veronica Lake and Brian Donlevy, as actors on the set of an actual movie, I Wanted Wings (see Creator Cameo below).
- Citizenship Marriage: The whole plot, as Georges decides to follow Anita's example in order to gain entry to the United States.
- Contrived Coincidence: Old lovers and dance partners Georges and Anita just happen to bump into each other years later, in a sleepy little border town on a different continent.
- Creator Cameo: Director Mitchell Leisen plays director Dwight Saxon. The film has Georges interrupting Leisen/Saxon on the set of a real Mitchell Leisen movie, I Wanted Wings.
- Diagonal Billing: Boyer and de Havilland are billed this way.
- Driven to Suicide: Georges winds up with a room at the Hotel Esperanza after its previous occupant, a German named Vexler, hangs himself.
- Driving a Desk: Throughout Georges and Emmy's honeymoon road trip; not quite as bad as most examples.
- Fainting: Beauvois does this after finding out he's a descendant of Lafayette and thus entitled to American citizenship.
- Finger-Twitching Revival: As Emmy starts to regain consciousness after being hospitalized for a car accident.
- Fourth-Date Marriage: What Georges is pressing for, and he gets it, marrying Emmy after a few hours acquaintance.
- Framing Device: Georges looks up an old casual acquaintance of his, film director Dwight Saxon, and tells him the whole story in a series of flashbacks.
- Gold Digger: Both Georges and Anita used to do this. Anita remains utterly unashamed about it, telling the inspector in the last scene that she has ensnared a Swedish businessman who doesn't speak a word of English and has $340,000 in the bank.
- Good Smoking, Evil Smoking: Emmy doesn't smoke and she tells Georges he should quit. On the other hand, Anita the vixen lights up a cigarette as she tells Emmy the unpleasant truth about Georges.
- Hollywood Law: A French immigrant gains entry to the USA when he is proved to be a descendant of the Marquis de Lafayette. The Marquis did really receive honorary citizenship (as did Winston Churchill), but honorary citizenship is not transferable to one's descendants.
- Let Off by the Detective: The immigration cop, Inspector Hammock, lets Georges off the hook and allows his entry into the USA, having been convinced that he really loves Emmy after all. A pretty generous example, as Georges barreled through the checkpoint and then led Hammock and the cops on a chase all the way to Los Angeles.
- Love Triangle: Georges the gigolo, Anita his slutty former lover, and Emmy, his new bride.
- Not Even Bothering with the Accent: American Paulette Goddard playing an Australian.
- Really Gets Around: Georges and Anita.Anita: All those years, with all those others, I've shut my eyes and thought of you. I want to keep them open once again, Georges.
- Romantic Fake–Real Turn: George scams Emmy into a quickie marriage. Naturally he falls in love with her for real.
- Sexy Discretion Shot: The film cuts away as a towel-clad Emmy and Georges embrace on the beach.
- Skinnydipping: Emmy's clothes are shown in a pile on the beach, then Emmy is shown from a distance cavorting in the ocean.
- Staggered Zoom: Done to show Emmy's school bus has appeared in town again, at a very bad time for Georges, as he's in the company of his girlfriend Anita as well as a U.S. immigration official.
- Title Drop: When putting the full-court press on Emmy, Georges compares them to two trains briefly at the same station, saying "We can't change our course, any more than we can hold back the dawn."