- 20-year ranking change: -15
-- 2024 rank: #30
-- 2004 rank: #15

Despite declining popularity, Cocker spaniels remain the second-most popular breed on this list. These dogs retain popularity owing to their stunning silky coats and gentle personalities. Prospective owners may, however, be straying away in recent years due to the thorough grooming that this breed requires. "Sessions missed are not easily made up and may result in tangles or mats in the Cocker's coat," the AKC warns.

- 20-year ranking change: -15
-- 2024 rank: #25
-- 2004 rank: #10

Good news, Chihuahua fans—even though these feisty little guys have fallen in popularity, they are the most popular breed on the list. Americans may be moving away from these dogs because of their reputation for having a big attitude. Without proper training, the AKC cautions that "this clever scamp will rule your household like a little Napoleon."

- 20-year ranking change: -16
-- 2024 rank: #63
-- 2004 rank: #47

As its name implies, the bullmastiff combines bulldog and mastiff bloodlines, bred to deter game poachers in 19th-century England. Though bullmastiffs make for loyal family pets today, potential owners may be wary of the breed's tendency toward stubbornness. They also have a well-known penchant for drooling—a bib might be needed to catch all that extra slobber.

- 20-year ranking change: -16
-- 2024 rank: #35
-- 2004 rank: #19

The fluffy white Maltese has been a beloved lapdog for thousands of years. These pups appear on ceramics from the Golden Age and even in the writings of Aristotle, who described the breed as "perfect in its small size." American pet owners, though, appear to disagree, perhaps because of the extensive grooming needed to keep a Maltese's coat at its best. However, the breed remains in favor elsewhere—in Korea, for example, the Maltese ranked as the most popular dog in 2023.

- 20-year ranking change: -17
-- 2024 rank: #120
-- 2004 rank: #103

Friendly and inquisitive, the smooth fox terrier was developed to accompany members of the English gentry on fox hunts. But the sport of fox hunting has declined since the early aughts—traditional fox hunting with dogs was banned in 2005—and consequently, so has the popularity of the smooth fox terrier. The U.K. Kennel Club reported that just 45 smooth fox terriers were born in 2024, a record low for the breed.

- 20-year ranking change: -17
-- 2024 rank: #109
-- 2004 rank: #92

The Norwegian elkhound is a spitz-type breed, known for its wolf-like appearance. The breed's two-ply coat may have something to do with its decline in popularity. As the AKC notes, "Elkhound breeders warn potential puppy buyers of the inevitable—that during shedding season they will have 'tumbleweeds' of silver undercoat rolling around their house."

- 20-year ranking change: -18
-- 2024 rank: #44
-- 2004 rank: #26

The Bichon Frisé has a delightful personality that matches its adorable looks. Often compared to clouds, these dogs are intelligent, affectionate, and even hypoallergenic. Like most curly-haired dogs, the Bichon Frisé requires extensive grooming and brushing, ideally every day, which may be too much for some dog owners.

- 20-year ranking change: -19
-- 2024 rank: #130
-- 2004 rank: #111

High energy is a defining characteristic of many terriers, including the Australian terrier. And that can be a lot to deal with, especially for owners who are daunted by the amount of exercise this pup requires. A lack of exercise leads to boredom, and, as the AKC notes, "Boredom leads to undesirable behavior." Aussies also love to dig—perhaps more than owners love holes in their yard.

- 20-year ranking change: -19
-- 2024 rank: #121
-- 2004 rank: #102

There are plenty of reasons to love the bearded collie, and just as many reasons why the breed may have dropped in the rankings. These canines are a little more high-maintenance than you might expect: The bearded collie's long coat requires daily grooming, its energetic nature means it needs tons of outdoor exercise, and its stubborn temperament can make training challenging.

- 20-year ranking change: -20
-- 2024 rank: #108
-- 2004 rank: #88

Spunky, friendly Welsh terriers were bred to hunt game and vermin in northern Wales. Since then, Welshies have served as beloved companions for John F. Kennedy, who brought his dog, Charlie, to the White House in 1961. The Welsh terrier may be falling out of favor nowadays due to its boundless energy, which requires significant exercise to keep in check.

- 20-year ranking change: -20
-- 2024 rank: #81
-- 2004 rank: #61

The chow chow's regal mane and distinctive blue-black tongue are two traits that make this dog unique. However, the breed may be decreasing in popularity due to its reputation for being aggressive. While Wag points out that any dog can have behavioral issues, chow chows "can be intensely territorial and have a naturally dominant personality."

- 20-year ranking change: -23
-- 2024 rank: #66
-- 2004 rank: #43

Cairn terriers earned their spot in American history when a little Cairn named Terry starred as Toto in "The Wizard of Oz." But while these dogs may be forever associated with pop culture iconography, they can be destructive diggers, extreme shedders, and disobedient walkers—especially if they find a smaller critter to chase. We're not saying Miss Gulch was right about Toto, but you can see why Cairns may not be the popular breed they once were.

- 20-year ranking change: -23
-- 2024 rank: #60
-- 2004 rank: #37

Bred by monks in the Swiss Alps in the 11th century, Saint Bernards are hardy pups who traditionally rescued pilgrims from avalanches. These days, Saint Bernards are known as affectionate family pets eager to please. Popularized by the 1992 movie "Beethoven," which featured a Saint Bernard in the titular role, these large dogs enjoy a reputation for friendliness and mischief. Decades removed from the classic film, however, that size and rascally behavior may be less appealing.

- 20-year ranking change: -24
-- 2024 rank: #101
-- 2004 rank: #77

The wire fox terrier's popularity has fallen sharply since the 1920s, when it was one of America's top 10 most popular breeds. Like its smooth-haired counterpart, this terrier was also bred for the hunt and now exhibits lots of personality. If not trained properly, that personality can manifest in "destructive and undesirable behaviors," per PetMD.

- 20-year ranking change: -24
-- 2024 rank: #91
-- 2004 rank: #67

Japanese chins belong to the toy group and have roots as the favorite pets of royals and aristocrats. These little guys are especially tiny at just seven to 11 pounds, which may make them too small for some dog owners, especially now that lap dogs are no longer the most coveted accessory. Their flat faces also make them prone to breathing problems.

- 20-year ranking change: -24
-- 2024 rank: #53
-- 2004 rank: #29

These stately hunting hounds are instantly recognizable by their sleek, silvery coats and amber or blue-gray eyes. The unique appearance of the Weimaraner has led to the occasional movie role—a Weimaraner named Rufus appeared in the 2002 rom-com "Maid in Manhattan." However, prospective owners should know the breed's need for abundant physical exercise, such as long runs and swims. According to the Weimaraner Club of America, "A tired Weimaraner is a good Weimaraner." However, the adage is one not every dog owner can live up to.

- 20-year ranking change: -24
-- 2024 rank: #36
-- 2004 rank: #12

Pugs with their flat, wrinkly faces and curly tails count the royals of China and Holland among their legions of fans. The centuries-old breed has also made several on-screen appearances, including in David Lynch's "Dune" in 1984, the "Men in Black" franchise starting in 1997, and, more recently, Netflix's 2021 animated release "The Mitchells vs. the Machines." Charming, affectionate, and versatile, pugs make excellent companions. Unfortunately, these dogs can fall prey to various health issues due to their distinctive short noses. They may require costly veterinary care throughout their lives, which could be why they've fallen out of favor.

- 20-year ranking change: -28
-- 2024 rank: #100
-- 2004 rank: #72

The petite, energetic Parson Russell terrier, or PRT, is a superstar in the hunting world and show business. A PRT named Uggie appeared in the 2011 movies "Water for Elephants" and "The Artist," for which he won the Palm Dog Award at the Cannes Film Festival. As cute as these little dogs may be, PRTs are far from lazy lap dogs. They need plenty of exercise and are clever enough to get up to all kinds of mischief, so prospective dog owners may have decided they're better enjoyed onscreen than in their homes.

- 20-year ranking change: -28
-- 2024 rank: #99
-- 2004 rank: #71

Silky terriers are small, measuring up to 10 inches tall and weighing around 10 pounds. Owners may be drawn to this breed for the glossy hair that gives them their name, which has been compared to human hair in consistency. As tiny as they are, silkies need more attention than many dog owners can offer. According to The Spruce Pets, "They might act out due to boredom or loneliness via problem behaviors, such as excessive chewing or barking."

- 20-year ranking change: -35
-- 2024 rank: #76
-- 2004 rank: #41

The shar-pei is still beloved, but there's a reason why the AKC calls this dog a "fascinating but challenging breed." Shar-peis have a distinctive look, including a "hippopotamus" muzzle, rolls of loose skin, and a blue-black tongue they share with chow chows. But their nature as guardian dogs means they are especially wary of strangers and dogs they don't know, making them very defensive and aggressive.

- 20-year ranking change: -38
-- 2024 rank: #142
-- 2004 rank: #104

Named after their ancestral homelands, a valley in Ireland's Wicklow Mountains, the Glen of Imaal terrier is an amiable and surprisingly athletic companion. Though you might not guess it from their short-legged stature, these dogs were bred for hunting and hard work, like turning roasting meat on spits over a fire. Though very sociable and affectionate around humans, Glen of Imaal terriers typically don't get along well with other dogs, which could explain their slide in popularity.

- 20-year ranking change: -42
-- 2024 rank: #80
-- 2004 rank: #38

Initially bred for Chinese royalty, Pekingese indeed appear regal. Their small stature, long coat, "lion's mane," and unique gait make them stand out, but they may not be for everyone. Families might have moved on to other breeds because the Pekingese notably does not get along well with younger children or with other dogs.

- 20-year ranking change: -47
-- 2024 rank: #86
-- 2004 rank: #39

Lhasa apsos may be falling in popularity for the same reasons they were once highly sought after. Originally bred for palaces and monasteries, these dogs have floor-length coats that require regular grooming and high-quality dog food to maintain good health. Finally, their regal background means that while they may become a beloved member of your family, they turn their noses up at new people.

- 20-year ranking change: -47
-- 2024 rank: #68
-- 2004 rank: #21

The miniature pinscher became all the rage in the early 20th century and enjoyed popularity through the years, but its prevalence has dropped dramatically. Cutely nicknamed the "king of toys," the mini pin is indeed a small dog with a big personality and lots of energy. Perhaps prospective owners have learned that these pups also come with their share of potential downsides, including excessive barking, territorial behavior, and a lack of obedience.

- 20-year ranking change: -72
-- 2024 rank: #112
-- 2004 rank: #40

The jowly Neapolitan mastiff has a long and colorful history. These dogs fought alongside the armies of ancient Rome and hunted with Italian nobles during the Renaissance era. Though the Neapolitan mastiff experienced a resurgence of popularity in its native Italy during the mid-20th century, the breed wasn't widely known until it appeared in the "Harry Potter" film franchise in the early 2000s. Despite its intimidating appearance, the Neapolitan mastiff is a sweet and tractable dog whose biggest threat may be its profuse amounts of drool—but that may be enough to turn people off, particularly as the "Harry Potter" movies become more distant memories.

Story editing by Louis Peitzman. Copy editing by Robert Wickwire.