This study is a systematic examination of the open access status of research in two flagship language testing and assessment journals: "Language Testing and Language Assessment Quarterly." Coding and analysing 898 articles, we investigated (a) the prevalence of open access in four aspects--open manuscripts, open materials, open data, and open code, and (b) the relationship between open access and various characteristics of research, tests, and researchers. Our study revealed a positive trend in the adoption of open access over time, with open manuscripts and materials showing notable increases. Open code and data have remained scarce, though with a recent uptick from a low base. Notably, logistic regression results suggest inequitable participation in open access as authors from the Global South were less likely to have open manuscripts. Recognising the potential role of flagship journals as trend and standard setters, we call on the field to (a) shift towards more equitable open access models, (b) balance intellectual property concerns with validation needs, (c) recognise open code and open data with protected access via dedicated badges, and (d) adopt Research Transparency Statements, a new reporting structure inclusive of methodological and epistemological differences in open research practices.