This paper presents the findings of a large-scale quantitative study, which involved surveying 1,184 undergraduates from a Thai science and technology university to assess both their general and language mindsets. The study's primary aims were to identify the prevalence of growth or fixed among these students, explore potential statistical variations in mindsets based on gender, year level, and perceived language proficiencies, and ascertain the relationships between mindsets, gender, year level, and perceived proficiency. Additionally, the research delved into the structural dimensions of their general and language mindsets. Descriptive, inferential and factor analyses were employed for data analysis. Descriptive analysis revealed that Thai undergraduate students predominantly embrace growth mindsets in both their general and language-related beliefs. Notably, t-test showed no significant disparities were detected among the variables examined, indicating a consistent mindset across various demographic groups. Moreover, correlational analysis identified relationships between general mindset, language mindset and perceived general language proficiency. Furthermore, language mindset showed significant associations with year level and perceived general language proficiency. In terms of the factorial structure, factor analysis yielded three distinct factors of general mindset, while the language mindset exhibited a unidimensional structure. Discussions included theoretical and pedagogical implications, as well as directions for future research in language mindset.