Dihydroartemisinin (DHA), an artemisinin derivative, can influence certain malignancies' inflammatory response and growth. This study used Cell Counting Kit-8 and Transwell assays to show that DHA suppressed the growth, migration, and invasion of medullary thyroid cancer cells. Furthermore, the authors used enzyme-linked immunosorbent assay, Western blotting, and immunofluorescence to confirm the expression of the transcriptional coactivators Yes-associated protein (YAP)/transcriptional coactivator with a PDZ-binding domain (TAZ) downstream of the Hippo pathway and changes in the expression of the epithelial-mesenchymal transition (EMT) process markers E-cadherin and N-cadherin. These results demonstrate that DHA effectively reduced the expression of interleukin (IL)-6 in medullary thyroid carcinoma (MTC) cells and hindered the EMT process by regulating the Hippo pathway. This regulation was achieved by promoting YAP phosphorylation and inhibiting YAP/TAZ protein expression. Additional activation of the Hippo pathway by GA-017 alleviated the inhibitory effect of DHA on IL-6. Hippo pathway activation led to an increase in the expression of E-cadherin, a marker of EMT. In conclusion, DHA was demonstrated to regulate the Hippo pathway by inhibiting IL-6 secretion, leading to the inhibition of EMT in MTC. These findings provide a theoretical foundation for further exploration of the anticancer mechanisms of DHA and offer valuable insights into its potential clinical application as a combinatorial drug.