Disclosed are an electronic device and a method of controlling a text-to-speech (TTS) rate. An electronic device may include a processor, and a memory configured to store instructions to be executed by the processor. The processor may receive a voice signal of a user. The processor may calculate a speaking rate of the voice signal based on the voice signal. The processor may generate an output text to be output to the user based on the voice signal. The processor may determine a TTS rate of the output text based on the speaking rate. The processor may convert the output text into voice data based on the TTS rate and output the voice data.