We examined the association between blood pressure (BP) in the early third trimester and hypertension 10-14 years after delivery per American College of Cardiology and American Heart Association recommendations. We conducted a secondary analysis using the prospective HAPO FUS (Hyperglycemia and Adverse Pregnancy Outcome Follow-up Study) in patients without a chronic hypertension diagnosis. The exposure and outcome were systolic and diastolic BP measured in the early third trimester and 10-14 years after delivery, respectively. Among 4,697 participants in the HAPO FUS, at 10-14 years after delivery (median age 41.6 years), 8.3% had elevated BP, 14.1% had stage 1 hypertension, and 6.1% had stage 2 hypertension. Compared with normal BP, elevated BP in the early third trimester was associated with an increased risk of stage 1 hypertension (adjusted odds ratio [aOR] 2.76; 95% CI, 1.91-4.00) and stage 2 hypertension (aOR 3.76; 95% CI, 2.28-6.19). Stage 1 hypertension was associated with an increased risk of stage 2 hypertension (aOR 6.16; 4.24, 8.94). Pregnant individuals with high BP in the third trimester were at increased risk of developing hypertension 10-14 years after delivery.