Teachers' capabilities to conduct classroom assessment and use assessment evidence are central to quality assessment practice, traditionally conceptualised as assessment literacy. In this paper we present, firstly, an expanded conceptualisation of teachers' assessment work. Drawing on research on teacher identity, we posit that teachers' identity as professionals, beliefs about assessment, disposition towards enacting assessment, and perceptions of their role as assessors are all significant for their assessment work. We term this reconceptualisation Teacher Assessment Identity (TAI). Secondly, in support of this conceptual work, we present findings from a systematic review of self-report scales on teacher assessment literacy and teacher identity related to assessment. The findings demonstrate that such scales and previous research exploring teacher assessment practices have paid limited attention to what we identify as essential and broader dimensions of TAI. We share our reconceptualisation and analyses to encourage others to consider teacher assessment work more broadly in their research.