Techniques for determining pulse transit time (PTT) and blood pressure measurements based on stethoscope data are provided. In one example, a system comprises a stethoscope component that monitors a heart and generates stethoscope data representative of a sound wave generated by the heart. The system can further comprise an analysis component that receives the stethoscope data and receives, from a photoplethysmography (PPG) component that monitors an extremity, PPG data representative of a pulse wave at the extremity. The analysis component can determine, based on the stethoscope data, a first time corresponding to closure of a tricuspid valve of the heart and can determine a PTT as a function of the first time and a second time corresponding to the pulse wave at the extremity that is determined based on the PPG data. Blood pressure measurements can be obtained from algorithms with the inputs of PTT or times determined based on the PPG data.