The paper presents an expert-curated benchmark for assessing Ukrainian proficiency in LLMs, focusing on grammar and orthography as core components of language competence. Prepared by professional linguists, the proposed gold-standard dataset is designed to test normative Ukrainian usage.The benchmark is further used to evaluate a range of LLMs, including Ukrainian-focused, multilingual, and large-scale models, under zero-shot and few-shot prompting in Ukrainian and English. Across these settings, smaller models achieve no more than 42.1% accuracy, while large-scale LLMs reach up to 59.6%. These results show that standard Ukrainian remains challenging for current LLMs and highlight the need for stronger language-specific evaluation and adaptation.