Microplastics (MPs; defined as plastic debris smaller than 5mm) have emerged as one of the fastest-growing forms of pollution across habitats. Environmental pollutants are contributing to the global decline of natural populations, with MPs representing a particularly widespread and persistent threat. The extent to which MPs affect the growth and health of animals remains unclear across various taxa, notably among amphibians, which represent the most endangered group of vertebrates. Here, we used the fully aquatic African clawed frog (Xenopus laevis) to investigate the effects of polyethene MPs on the development and health of its filter-feeding larvae. Xenopus larvae were exposed to an environmentally relevant concentration of MP particles in the absence or presence of exogenous stress hormone corticosterone (CORT), the latter to induce a neuroendocrine stress response. To assess the physiological consequences of MP exposure, our study quantified markers of stress (CORT), or health and ageing (oxidative stress levels and telomere length) in larvae. MP exposure was found to reduce the larval body mass but it did not include changes in the skeletal growth (body length). CORT levels, oxidative stress, and telomere length remained unaltered in larvae exposed to MPs. Our results confirm that environmentally relevant concentrations of MPs reduce body mass but suggest that such effects might not have major consequences for the stress status, health, and ageing rates of filter-feeding amphibian larvae.