High school students' beliefs toward their abilities could be fixed or malleable, and mindset may differ between boys and girls. The aim of this article is three-fold: to examine the beliefs of students as to whether their abilities are fixed or malleable in the context of English language learning, to know if mindsets of boys and girls are significantly different, and to provide an understanding of what difficulties students face in English language learning. Using a modified mindset survey, data from 467 students enrolled in regular programs in public schools in Bangkok was analyzed quantitatively. Findings indicated that students have a growth mindset on their own ability, others' success, criticisms, obstacles, and challenges. However, they tend to have a fixed mindset about putting effort into learning English. Similar to previous studies, there was no significant difference found between girls' and boys' mindsets. Concerning difficulties faced by students in an EFL setting, cognitive, affective challenges, and other challenges were coded. Cognitive challenges cover difficulties in remembering grammar rules and vocabulary, difficulties in understanding some words and accented speech, difficulty in translating from L2 to L1, difficulty in selecting words to use in a specific context, difficulties in listening, reading, and writing, lack of vocabulary knowledge and knowledge about basic English, lack of ability to speak English and practice to speak English, and slow cognitive processing. Meanwhile, affective challenges include fear of making mistakes, high anxiety, lack of interest in studying grammar rules, and lack of selfconfidence and attentiveness. Other codes include negative peer influence and perceived negative teacher acts. Teaching and research implications are discussed to help students build a growth mindset because challenges are ubiquitous in English language learning.