Background: Thyroid dysfunction during pregnancy is a common endocrine disorder with significant implications for maternal and fetal health, particularly in relation to hypertensive complications. The purpose of the study was to determine the prevalence and pattern of subclinical thyroid dysfunction in hypertensive compared to normotensive pregnant women. Methods: This cross-sectional, comparative study was conducted at the Department of Obstetrics & Gynaecology, Dhaka Medical College Hospital, Dhaka, Bangladesh, from February 2020 to March 2021, including 220 pregnant women (110 hypertensive, 110 normotensive). Socio-demographic and obstetric data were collected, blood pressure measured, and 5 mL venous blood samples analyzed for serum TSH and FT4 using chemiluminescent immunoassay. Subclinical thyroid disorders were defined by trimester-specific reference ranges, data were analyzed with SPSS v25 (p < 0.05). Results: In 220 pregnant women, hypertensive and normotensive groups were comparable in age, gestation, and parity. Subclinical hypothyroidism was higher in hypertensive women (46.4% vs 14.5%), euthyroidism predominated in normotensive women (83.6% vs 39.1%), and higher blood pressure was associated with increased thyroid dysfunction. Hypertensive women also had higher TSH (4.46 vs 2.28 µIU/mL) and lower FT4 (13.49 vs 15.78 pmol/L), both significant (p = 0.001). Conclusion: Hypertensive pregnant women have a higher prevalence of subclinical hypothyroidism and altered thyroid hormone levels compared to normotensive women, highlighting the need for early thyroid screening in this population.