Millions of companion animals are relinquished to shelters each year. For each dog entering, their characteristics and the characteristics of the shelter holding him/her influence their time to adoption. Using a Cox proportional hazards frailty model, these issues were explored using data from 31 shelters within the British Columbia Society for the Prevention of Cruelty to Animals shelter system. Results indicated that surrender reason, age, original source, coat color, breed, human population density of the shelter location, and year the nonhuman animal entered the shelter significantly influenced time to adoption. This study identified characteristics of dogs that make them less likely to be adopted quickly. Given limited resources, these results may help inform shelters on how to best allocate resources, particularly in interventions to improve adoption rates in shelters.