Overview
The Army Officer Selection Board (AOSB) is the British Army's selection process for candidates applying to become officers, run at the selection centre in Westbury, Wiltshire. It has two stages: AOSB Briefing and AOSB Main Board. Only candidates who pass the Briefing are invited to Main Board, and only candidates who pass Main Board can go on to officer training at the Royal Military Academy Sandhurst (RMAS).
Levels or stages
AOSB Briefing
A 2-day visit to Westbury where candidates are assessed on physical and practical exercises and briefed on what Main Board requires. Candidates also sit a series of aptitude tests covering verbal reasoning, numeracy and abstract reasoning, which combine into an Officer Intelligence Rating carried forward to Main Board. Based on performance, candidates are placed in a category that lets them proceed to Main Board immediately or requires a delay of between 3 and 24 months before reattempting.
AOSB Main Board
A 4-day assessment at Westbury, the final and most comprehensive stage, evaluating leadership, physical fitness, planning exercises, group tasks and interviews to judge suitability for officer training.
Who can apply
Applicants must meet the British Army's general eligibility criteria for officer entry, including age, nationality/residency, educational qualifications appropriate to the officer route applied for, and medical and fitness standards.
After the exam
Candidates who pass AOSB Main Board proceed to officer training at the Royal Military Academy Sandhurst.
Preparation tips
Because the Officer Intelligence Rating from Briefing carries forward to Main Board, preparing for the verbal, numerical and abstract-reasoning tests before the Briefing stage — not just the physical and practical exercises — affects outcomes at both stages.
What are the two stages of AOSB?
AOSB Briefing, a 2-day assessment that also sets an Officer Intelligence Rating, followed by AOSB Main Board, a 4-day assessment that is the final stage before Sandhurst.
What happens if a candidate does not pass AOSB Briefing?
Depending on their category, they may be required to wait between 3 and 24 months before they can reattempt the process.