Objective: To describe and classify the neurological trajectories in patients with mild neurological forms of ataxia telangiectasia (A-T) from the Dutch A-T cohort, combined with patients reported in the literature. Methods: Clinical, genetic and laboratory data of 14 A-T patients with mild neurological phenotypes from the Dutch cohort were analyzed and combined with corresponding data from the literature. A mild neurological phenotype was defined by a later onset, non-ataxia presenting or dominant feature, or slower progression compared to the classical A-T phenotype. Neurological trajectories were classified based on age of onset, presenting feature and follow-up data. Results: 105 patients were included in the study. Neurological trajectories were categorized into six groups: patients with childhood-onset extrapyramidal features with cerebellar symptoms developing later (group 1; 18 patients), childhood-onset cerebellar symptoms, with extrapyramidal features developing later (group 2; 35 patients), childhood to adolescence-onset dystonia, without cerebellar symptoms (group 3; 23 patients), childhood to adolescence-onset isolated cerebellar symptoms (group 4; 22 patients), childhood to adult-onset prominent muscle weakness (group 5; 2 patients), and patients with adult-onset extrapyramidal features, with anterior horn cell disease arising subsequently (group 6; 5 patients). Conclusions: This systematic study of the different motor abnormalities and their course over time in A-T patients with mild phenotypes, enabled us to recognize six essentially different phenotypic patterns. Awareness of these different trajectories of motor abnormalities in milder forms of A-T will contribute to a reduction of diagnostic delay in this severe multisystem disorder.