Male vs Female Shih Tzu: Real Differences in Size, Temperament, and Care
How we researched this guide: This article is based on the American Kennel Club (AKC) Shih Tzu breed standard, VCA Animal Hospitals guidance on heat cycles, and a 2024 UK study of dog longevity led by Dogs Trust. Last reviewed: September 2026.
Should you choose a male or a female Shih Tzu? The honest answer is that individual personality, upbringing, and whether the dog is spayed or neutered matter far more than sex. Still, there are a few real differences worth knowing.
Quick Comparison
| Factor | Male | Female |
|---|---|---|
| Size | Same AKC ideal for both: 9 to 10.5 inches, 9 to 16 pounds | Same AKC ideal for both |
| Temperament | Individual; the breed standard calls for a friendly, trusting nature in all Shih Tzus | Individual; same standard applies |
| Heat cycles | None | Unspayed females come into heat, often twice a year |
| Marking | Unneutered males are more likely to leg-lift and mark | Less common, but some females mark |
| Lifespan | Slightly shorter on average across all dogs in one large UK study | Slightly longer on average across all dogs |
| Spay or neuter cost | Usually less | Usually more, as spaying is a larger surgery |
Size and Appearance
The AKC breed standard does not set different sizes for males and females. It gives the same ideal for all Shih Tzus: 9 to 10.5 inches at the shoulder and 9 to 16 pounds. Some males may look a little sturdier, but there is a lot of overlap.
Temperament
The AKC standard asks for the same temperament in every Shih Tzu: outgoing, happy, affectionate, friendly, and trusting towards all. You will hear claims that males are more cuddly or females more independent, but these are generalizations. Meet the individual dog, ask the breeder or rescue about personality, and focus on early socialization and reward-based training.
Female Shih Tzus: Heat Cycles
VCA Animal Hospitals notes that small-breed dogs often have their first heat around six months of age and may cycle two or three times a year. Each heat lasts about 9 days on average, but can range from 2 to 24 days. Signs include a swollen vulva, bloody discharge, and more frequent urination. A female can become pregnant during heat, so keep her away from intact males. Our breeding guide covers the cycle in more detail.
Male Shih Tzus: Marking and Roaming
Unneutered males are more likely to lift a leg and mark territory, and may be more interested in females in heat. Neutering can reduce some hormone-driven behaviors, especially when combined with training. Read our spay and neuter guide for timing and pros and cons.
Health and Lifespan
A 2024 study of UK dogs led by Dogs Trust found that, across all breeds, females lived slightly longer than males on average: 12.7 years compared with 12.4 years. This is a small, population-level difference. It does not mean any individual male will live a shorter life. For breed-specific data, see our Shih Tzu lifespan guide.
Unspayed females face risks such as uterine infection and mammary tumors, while unneutered males can develop testicular and prostate problems. Talk to your vet about the right plan for your dog.
Which Should You Choose?
- Choose the individual, not the sex. Energy level and personality matter most.
- Think about spay or neuter plans. These reduce many of the differences.
- If you already have a dog, ask a trainer or your vet about the best match.
- Meet the puppy’s parents if possible, to get a sense of adult temperament.
Safety first: An unspayed female can develop pyometra, a serious uterine infection that needs emergency care. Signs include drinking more, low energy, a swollen belly and discharge from the vulva, often in the weeks after a heat. Talk to your vet about spaying or neutering and the right timing for your dog.
Frequently Asked Questions
Are male or female Shih Tzus better?
Neither is better overall. Personality, upbringing, training, and spay or neuter status matter more than sex. Meet the individual dog before deciding.
Are male Shih Tzus bigger than females?
The AKC standard gives the same ideal size for both: 9 to 10.5 inches tall and 9 to 16 pounds. Some males look a little sturdier, but there is a lot of overlap.
Do female Shih Tzus have periods?
Unspayed females have heat cycles. VCA notes that small breeds often start around six months of age and may cycle two or three times a year, with each heat lasting about 9 days on average.
Do male Shih Tzus mark more?
Unneutered males are more likely to lift a leg and mark. Neutering and training can reduce marking.
Do female Shih Tzus live longer?
A 2024 UK study of all dog breeds found females lived slightly longer on average, 12.7 years versus 12.4 years. This is a small population-level difference.
Sources
- American Kennel Club: Official standard of the Shih Tzu
- VCA Animal Hospitals: Estrous cycles in dogs
- Liverpool John Moores University: Dog longevity study (McMillan KM, et al., Scientific Reports, 2024)
This article is for general information. It is not a substitute for advice from your veterinarian. Read our medical disclaimer.
