Introduction: Erosive tooth wear has a multifactorial origin, where multiple risks contribute to its initiation and subsequent progression. The prevalence of tooth wear varies among countries; therefore, national studies are needed to examine the prevalence of this condition and its associated determinants. Materials and Methods: A sample of this national study included a total of 1,397 adults (response rate of 52%). Severity and number of teeth with erosive tooth wear, caries experience (D3MFS), and fluorosis were assessed clinically. A self-reported questionnaire inquired about sociodemographics, oral health behavior, diet, and general health. Fluoride levels in drinking water at the recruitment areas were also recorded. Data were analyzed by bivariate and multivariate methods. Results: The prevalence of erosive tooth wear in enamel and dentin combined was 59% among 35- to 44-year-old, 75% among 45- to 54-year-old, 70% among 55- to 64-year-old, and 66% among 65- to 74-year-old males. The prevalence among females in the respective age groups was 44, 60, 63, and 59%. Erosive tooth wear in enamel was associated with a lower fluoride level (≤1 ppm) in the drinking water (OR 2.1, 95% CI 1.1–4.2). Erosive tooth wear in dentin was positively associated with male gender (OR 1.7, 95% CI 1.1–2.5), periurban/rural residency (OR 1.6, 95% CI 1.1–2.4), older age (OR 1.6, 95% CI 1.3–1.9), presence of reflux (OR 3.3, 95% CI 1.0–10.9), and negatively with higher D3MFS scores (OR 0.7, 95% CI 0.5–0.9). Conclusions: The prevalence of erosive tooth wear in enamel and dentin was relatively high in Lithuania; the erosive tooth wear in enamel and dentin combined was 52% among 35- to 44-year-olds, 68% among 45- to 54-year-olds, 67% among 55- to 64-year-olds, and 63% among 65- to 74-year-olds. Lower fluoride level in drinking water was associated with erosive tooth wear in enamel. Male gender, residency in periurban/rural areas, older age, and presence of acid reflux were associated with higher odds, while higher D3MFS scores were associated with lower odds for erosive tooth wear in dentin. These results can be used to plan dental public health prevention.