Assessing student writing constitutes the major portion of second language writing teachers’ workloads; however, studies assessing and quantifying teachers’ writing assessment literacy (knowledge, beliefs, practices) are comparatively rare. In the present study, second language writing instructors from tertiary institutions (N = 702) were surveyed. Data were collected with a 54-item survey instrument administered through SurveyMonkey®. Items were formulated to ascertain writing teachers’ backgrounds and perspectives on assessment using multiple choice, Likert-scale, and open-ended response items. Analysis focuses on four research questions: (1) How have second language writing teachers obtained assessment knowledge? (2) What do second language writing teachers believe about writing assessment? (3) What are the assessment practices of second language writing teachers? (4) What is the impact of linguistic background and teaching experience on writing assessment knowledge, beliefs, and practices? Teachers reported training in writing assessment through graduate courses, workshops, conference presentations; however, nearly 26% of teachers in this survey had little or no training. The results also showed relative effects of linguistic background and teaching experience on teachers’ writing assessment knowledge, beliefs, and practices.