May Measurement Month (MMM) is a global campaign initiated by the International Society of Hypertension (ISH) with the aim of raising awareness of high blood pressure (BP) and serving as a catalyst for the establishment of screening programmes around the world. An opportunistic cross-sectional survey of volunteers aged ≥18 years was conducted. A standardized protocol for MMM was used to measure BP and collect relevant health information from participants at screening sites in four regions of Ghana. Hypertension was defined as a systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg or on antihypertensive medication. A total of 4832 people agreed to take part in the MMM21 study and were screened. After multiple imputation of missing BP readings, 1426 people (29.5%) had hypertension. 11.9% of the 1426 participants with hypertension were aware of their condition, and 8.6% reported taking antihypertensive medication. 24.2% of 123 people on antihypertensive medication had their BP under control (<140/90 mmHg). In addition, only 2.1% of the 1426 participants with hypertension had controlled BP. Results from this study found that almost nine out of 10 people with hypertension who were screened were unaware of their condition, most were untreated, and only 2% of those with hypertension had their BP controlled with medication. This emphasizes the importance of BP screening campaigns as a tool for identifying and referring people with high BP for treatment.