🐾 Vet-Reviewed · AKC & Texas A&M Sources · 2026
Puppy Development Timeline
Birth to 12 Months
A week-by-week guide to every physical and behavioural milestone — from eyes opening at 2 weeks to full adolescence at 52 weeks. What to expect, what to do, and when to call your vet.
Neonatal (0–2 wks)
Transitional (2–4 wks)
Socialization (4–12 wks)
Juvenile (3–6 mo)
Adolescent (6–12 mo)
Day 10–14
Eyes open for the first time
Week 3
Ears open, hearing begins
Week 3–4
First baby teeth emerge
Week 6–8
First vaccinations due
Week 8
Ideal age to go to new home
Week 3–12
Critical socialisation window
Sources: American Kennel Club Puppy Growth Timeline (2025) · Texas A&M Veterinary Medicine & Biomedical Sciences, Harmony Diers CVT · Best Friends Animal Society Puppy Development Stages · Seattle Humane Society Developmental Stages · Dogster, vet-reviewed puppy development guide (January 2025) · Pet Care Medical week-by-week guide (April 2026). Timelines represent breed averages — individual puppies vary. Always consult your veterinarian for personalised health and vaccination guidance. Published by lifeatherpaw.com — last updated May 2026.