Aims: The primary focus of this empirical study was to investigate the factors influencing the level of GAP adoption for cucurbit vegetable in the Anuradhapura district of Sri Lanka. Study Design: Three-stage purposive and proportionate sampling Place and Duration of Study: The study was carried out in the Anuradhapura district, North Central Province of Sri Lanka in 2018. Methodology: Primary and secondary data were used in the study. The primary data were collected mainly through a field survey using a structured and pre-tested questionnaire. The total sample size was 120. Key informant interviews (KII), and a focus group discussion (FGD) were conducted to triangulate data and information obtained from the questionnaire survey and to obtain additional qualitative information. Descriptive analytical techniques, analysis of variance (ANOVA) test, and the General Linear Model (GLM) were employed for the data analysis. Results: Results revealed that 40% of respondents are moderate level GAP adopters, whilst about 68% practiced more than half of the recommended GAPs. The results of ANOVA revealed that farmers who adopted a higher proportion of GAPs earned a higher farming income, than those who practiced a moderate or low proportion of GAPs. Similarly, when compared to moderate and poor level GAP adopters, the average cost of production of higher-level adopters decreased significantly (p < 0.05). The results of the regression analysis revealed that farmer awareness of GAPs, farmer education level, farming experience, farming income, and cost of cultivation have a significant (p < 0.05) effect on the level of GAP adoption by cucurbit farmers. Conclusion: Awareness of GAPs, farmer education level, farming experience, and farming income significantly affect the adoption level of GAPs. Policy priority should be given to planning for a long-term farmer awareness program on GAPs through proper training and extension programs.