Nepal launched its COVID-19 vaccination campaign in January 2021 through the COVID-19 Vaccines Global Access (COVAX) facility. Vaccine coverage, especially in low- and middle-income countries (LMICs), is measured using administrative-level data; however, this source is often subject to biases and limitations. We conducted a household survey in rural Sarlahi District, Nepal, to estimate COVID-19 vaccine coverage and assess associations with participant characteristics among adults. The quantitative household survey was conducted from August to December 2022 in four municipalities among 362 adults aged 18 years and older. The survey collected demographic data, vaccination status and vaccination accessibility details. Descriptive analyses included a summary of vaccination coverage, vaccine card availability, drop-out rate, and vaccine manufacturer. Multivariable regression modeling was used to analyze factors associated with completing the primary vaccination series. Three-quarters of participants (74.6%) completed at least the primary series (51.9% only completed the primary series, 22.7% were also boosted). Vaccine card retention was 86% among those with at least one dose. Odds of completing the primary series increased with age (31-50 yrs, adjusted odds ratio (aOR) = 3.07, 95% CI: (1.67, 5.8) and 51 + years, aOR = 4.75, 95% CI: (2.06, 11.9) compared to 18-30 years). Wealthier groups had higher odds of completing the primary series than the poorest quartile (wealth quartile 2, aOR = 3.04, 95% CI: (1.41, 6.80); wealth quartile 3, aOR = 2.18, 95% CI: (1.05, 4.62); wealth quartile 4, aOR = 2.32, 95% CI: (1.06, 5.17)). Despite moderate primary series coverage and high card retention, booster coverage remained low. The population has exhibited a mix-and-match approach to COVID-19 vaccination, likely due to availability and accessibility. While the emergency stage of the pandemic has ended, lack of adequate vaccine coverage increases the immunity gap for a virus that continues to circulate and evolve.