This study investigated the transfer of plastic debris in a terrestrial environment from the soil to a plant (the mung bean, Vigna radiata), and then to a consumer (the African giant snail, Achatina fulica). Adverse effects of these plastic pollutants on the physiology of the plant and animal were investigated. The mung bean plants were directly exposed to nanoplastics (NPs) by adding NPs to the soil for 10 days. The snails were indirectly exposed by feeding them for 14 days the leaves of mung bean plants that had internalized NPs. We found that NPs decreased their root growth (82.9 and 83.3% of control growth at low and high concentrations, respectively) and led to particle accumulation in the leaves of the mung bean plants. Meanwhile, the growth rate (77.1 and 62.0% of the control rate at low and high concentrations, respectively) and feeding and foraging speeds (63.4 and 54.0% of control speeds at low and high concentrations, respectively) of the snails were decreased by dietary NP intake. This was associated with decreased gut microbiota viability and histological damage to the digestive organ tissues of the snails. Thus, NPs negatively affect the growth of plants and the animals that consume them in terrestrial ecosystems, which could have adverse effects at higher trophic levels.