Introduction Rheumatoid arthritis (RA) is a chronic autoimmune disorder with variable disease course including periods of flares and remissions. High disease activity in terms of disease activity score-28 (DAS-28) results in significant morbidity. Hypothyroidism is found to be associated with higher DAS-28 scores in RA. This study is planned to determine overt and subclinical hypothyroidism and its correlation with the DAS-28 score in patients with RA. Methodology This study was conducted from June 2021 to March 2022 at the department of rheumatology and immunology at Shaikh Zayed Hospital, Lahore, Pakistan. Inclusion criteria were any male and female patients aged between 18 and 70 years. The blood samples of diagnosed patients with RA were sent for thyroid function tests (thyroxine [FT4], thyroid-stimulating hormone [TSH]), and erythrocyte sedimentation rate (ESR), and the patients were categorized as overt hypothyroidism, subclinical hypothyroidism, and non-hypothyroid. The collected data were analyzed on Statistical Package for the Social Sciences (SPSS) version 24.0 (IBM Corp., Armonk, NY). Results The mean age of patients was 38.18 ± 9.78 years. The mean duration of symptoms was 14.65 ± 1.04 months. There were 182 (91%) females and 18 (9%) males. The mean number of swollen joints was 2.26 ± 2.8, and the mean number of tender joints was 4.16 ± 5.11. Sixty patients (30%) had high disease activity, i.e., DAS-28 score > 5.1. Fifty-seven patients (28.5%) with RA had subclinical hypothyroidism, and 19 patients (9.5%) had overt hypothyroidism. Pain visual analog scale (VAS) and DAS-28 were significantly higher in hypothyroid patients. Conclusion It was concluded that patients of RA with concomitant hypothyroidism had increased disease activity with increased tender joints. Thyroid function tests should be included in the clinical evaluation of RA patients. The evaluation of thyroid functional status must be done during screening in RA patients. This will detect thyroid disorders earlier, with early treatment initiation and possibly a better prognosis.