Hypertension, a common cardiovascular disease (CVD) risk factor, is usually diagnosed and treated based on blood pressure readings obtained in the clinic setting. Blood pressure may differ considerably when measured in the clinic versus outside of the clinic setting. Over the past several decades, evidence has accumulated on two approaches for measuring out-of-clinic blood pressure: ambulatory blood pressure monitoring (ABPM) and home blood pressure monitoring (HBPM). Blood pressure measures on ABPM and HBPM each have a stronger association with CVD outcomes than clinic blood pressure. Controversy exists whether ABPM or HBPM is superior for estimating CVD risk, and under what circumstances these methods should be used in clinical practice for assessing out-of-clinic blood pressure. This review describes ABPM and HBPM procedures, the blood pressure phenotypic measures that can be ascertained, and the evidence that supports the use of each approach to measure out-of-clinic blood pressure. This review also describes barriers to the successful implementation of ABPM and HBPM in clinical practice, proposes core competencies for the conduct of these procedures, and highlights important areas for future research.