Ruth Kirk may refer to

• Ruth Kirk - wife of New Zealand Prime Minister Norman Kirk
• Ruth Kirk (author) - author, naturist, and PBS filmographer from Washington State
• Ruth M. Kirk - American politician from Maryland

• Thyridia
• Thyridia psidii
• Thyridia themisto
• Thyridiphora calidella
• Thyridiphora fenestrata
• Thyridiphora furia
• Thyridiphora gilva
• Thyridophora
• Thyridophora gilva
• Thyridopsis monotona
• Thyridospila fasciata
• Thyrioclostera
• Thyrioclostera trespuntada
• Thyriscus
• Thyriscus anoplus
• Thyristor conduction angle
• Thyristor converter
• Thyristor switched capacitor
• Thyristor-switched capacitor
• Thyristor valve
• Thyroditis
• Thyrogonia aurantiiventris
• Thyrogonia cyaneotincta
• Thyrogonia efulensis
• Thyrogonia hampsoni