Doug Harris (Josh Gad) is a lovable but socially awkward groom-to-be with a problem: he has no best man. With less than two weeks to go until he marries the girl of his dreams (Kaley Cuoco-Sweeting), Doug is referred to Jimmy Callahan (Kevin Hart), owner and CEO of Best Man, Inc., a company that provides flattering best men for socially challenged guys in need. What ensues is a hilarious wedding charade as they try to pull off the big con, and an unexpected budding bromance between Doug and his fake best man Jimmy.

Away for a romantic weekend where he had planned a grand gesture, Mick Turner and Olivia Pershing, co-proprietors of the Willow Lake Inn in Vermont, the inn's bread and butter business being weddings, are called back to the inn with the grand gesture having to wait when they learn that Olivia's daughter, Grace Pershing, to who Olivia gave her Long Island staging business in moving to Willow Lake, has showed up unexpectedly with her musician boyfriend, Eric Stratton, to announce their engagement. What Mick concurrently learns is that their next wedding clients - Abby Russo and Rob Atwell - have come a few days earlier than expected. While Mick, who has not worked directly on the wedding part of the business leaving such to Olivia, and to his daughter Julie before Olivia, vows to take care of Abby and Rob's wedding so that Olivia can focus on Grace and Eric, Olivia instead funnels all her A-type energies on Grace, turning into Motherzilla of the bride-to-be. Things between Olivia and Grace may get even more intense when Grace tells her the other news she has about what she intends to do when Eric and his band go on tour. What Mick does not anticipate in taking over whatever needs to be done for Abby and Rob is that Abby, from modest means marrying into an extremely wealthy family she does not know well, wants to make one change after another from her relatively simple but romantic initial wedding plans in wanting to impress the Atwells, especially when Rob's rather in-your-face younger sister, Kelsey Atwell, implies that "this is the way that it should be done" especially to match Rob and Kelsey's parents' wedding which was held at the inn years ago. Trying to impress may also change Abby's life aspirations in working as an artist full-time which is what she really wants instead of going back to law school which she almost completed before she had to drop out when her mother passed.

Still working in her parents' Greek restaurant, Toula Portokalos' daughter, Paris, is growing up. She is getting ready to graduate high school and Toula and Ian are experiencing marital issues. When Toula's parents find out they were never officially married, another wedding is in the works. Can this big, fat, Greek event help to bring the family together?

Hard-partying brothers Mike (Adam Devine) and Dave (Zac Efron) place an online ad to find the perfect dates (Anna Kendrick, Aubrey Plaza) for their sister's Hawaiian wedding. Hoping for a wild getaway, the boys instead find themselves outsmarted and out-partied by the uncontrollable duo.

Two talkative and bitter people, Frank and Lindsay, meet on the way to the same destination wedding. Frank is scarred from a bad family history, and Lindsay is heartbroken from a previous relationship. At first, they do not get along. However, isolated from the other wedding guests, the two spend a lot of time together. Despite their verbal sparring, they eventually form a connection and have to decide whether or not to stay with each other after their trip is over.

Youngstown, Ohio and teaching at Youngstown High was supposed to be a short stop in Debbie Taylor's life as she figured out a way to get back into the pop music business, of which she has been a part since she was fifteen. But close to one year later and having been provided an opportunity to reenter the business, she sees Youngstown, teaching the music program and running the music studio as her life. The main part of her happiness in Youngstown is falling in love with the school's guidance counselor, Noah Burns. So when he asks her to marry him, she accepts. Because of their commitments to the school, they have to plan their wedding quickly to coincide with the summer break while being able to squeeze in a honeymoon to Paris. However, the closer the wedding approaches, the more music business opportunities come Debbie's way. With Debbie's life tugging at her in opposite directions, she and Noah have to decide if they being married to each other and living in quaint Youngstown are in the cards for them, despite their love for each other.

NOUSHA HASSANI wants to marry the perfect Persian husband for her perfect Persian family. But her plans are derailed when she falls in love with ALEX TALBOT, an eccentric artist. When her traditional Muslim parents discover the two living together as domestic partners, they insist they officially get married. Nousha reluctantly agrees and the TALBOTS and the HASSANIS come together for a big Persian wedding. Over the course of one weekend, buried family wounds come rocketing to the surface, disaster ensues, and the couples relationship is tested.

As her Christmas Eve wedding draws near, Jennifer is visited by an angel and shown what could have been if she hadn't denied her true feelings for her childhood best friend.

A manager of an orphanage in Kolkata travels to New York to meet a benefactor.

Country singer Zane and fiancée Jeannette's wedding is interrupted by the last leg of a contractually obligated tour, leading them on a roundabout journey back to one another. After a video of Zane saving a female fan goes viral, Zane finally becomes the country music superstar he's always dreamed of being. Jeannette is happy and supportive, but after he misses their new wedding date, she begins to worry his dreams may no longer have room for her. Jolene lends her wisdom, but she needs to face up to her own past first. Quinn and Nana Suze share a lesson that sets up a beautiful finish at the wedding - if it ever happens.

During wedding season, strangers Brooke Etheridge, a physical therapist, and Nate Thomas, physical therapist and high-end classic-car restorer, are each attending four weddings on four consecutive weeks; each solely knows either the bride or the groom (or the bride or the bride, in one case). Neither has a plus-one either; Brooke has just broken up with Colin, which makes work life awkward because they're still business partners, and Nate is still recovering from his last long-term relationship, which ended just short of the altar. In an environment where there is pressure for singles to find romance at such events, both Brooke and Nate wish to avoid these romantic possibilities, and Brooke has also decided to stop dating for the summer to focus on herself. But in the fourth wedding, both are in the wedding party for their good friends Ginny and Greg--who both believe that Brooke and Nate would be a good match. Brooke and Nate recognize each other from a few somewhat-awkward previous encounters, and by the second wedding they have agreed to be wedding buddies to keep each other from those potential romantic-wannabe situations initiated by fellow wedding guests. As they see each other at subsequent weddings and start to spend other (non-wedding) time together, they start to fall for each other, but neither realizes how the other feels.

When small-town wedding photographer Molly's baby sister gets engaged, she enters the budget-conscious couple in a contest and wins a dream wedding - an all-expenses-paid, celeb-worthy event at a historic Beverly Hills hotel, thrown by "planner to the stars," Terrence Roquefort. It all seems perfect but when the engaged couple seems uneasy with the new plans, and maid of honor duties bring Molly closer to the best man, her ex-boyfriend Cory, she reconsiders whose dreams she is trying to fulfill.

When Jack, a groomsman, leaves for his best friend's wedding several states away, he's asked to pick up Samantha, a stranded bridesmaid. Jack discovers they've met before and have had a less than friendly past.Plot summaryAdd synopsis