The growth and development of the stripe-faced dunnart, Sminthopsis macroura (Gould), a small insectivorous marsupial, was examined and described from birth to weaning (a period of 65–70 days). All observations and analyses were based on known-age individuals from a laboratory colony. Growth curves showing the regression of body weight, head, pes, crown–rump, tail and head+body lengths as a function of age were constructed. Relative growth was determined by calculating the instantaneous relative growth rate, k, and two major phases of growth were recognised: during Phase I (birth to about Day 54 post partum) growth rate was rapid, and during Phase II (about Day 55 to weaning) a deceleration in growth rate was apparent. Growth rate may decline because of regression of the mammary tissue associated with the commencement of weaning. No significant relationship was found between month of birth and growth rate, and preliminary evidence suggests that litters of different sizes may grow at varying rates during Phase II of the suckling period. Preserved and living specimens were used to examine the development of young from birth to weaning.