Purpose: This study aimed to evaluate the stability of phonological awareness (PA) and language achievements between kindergarten and first grade among Arabic-speaking children. Method: A total of 1,158 children were assessed in PA and language skills in both grades and were classified based on distinct and integrated achievements on PA and language following percentiles' cutoff criteria. The classification of distinct achievements constituted high, intermediate, low, and very low achievement-based groups for each domain. The classification of the integrated achievements on both domains constituted four groups: intermediate-high PA and language, very low PA, very low language, and doubly low (very low PA and language). Descriptive statistics and McNemar's tests were used to examine the stability of these groups. Results: The analyses showed a significant improvement in achievements on most tasks. The distinct classification for PA and language indicated that many more kindergarteners in the extreme distribution with high and very low achievement levels maintained this profile in first grade compared to those with intermediate achievements. For PA, 55.7% of kindergarteners with high, 30% with intermediate, 30.4% with low, and 45.5% with very low achievements maintained their achievements in first grade. For language, 52.5% of kindergarteners with high, 34.5% with intermediate, 38.8% with low, and 59.8% with very low achievements maintained their language achievements. The integrated classification indicated a higher achievement stability rate for kindergarteners with intermediate-high PA and language (91.3%) and for doubly low achievers (84.7%) compared to very low PA (24.1%) or very low language (31.8%) achievers. Conclusions: The study indicated a higher variability in the distribution of the intermediate achievements compared to the high and very low achievements, which were more stable across grade. The results emphasize the need for dynamic linguistic assessments and early intervention for children with very low achievements in PA and language who show a poor prognosis.