This question is tricky to answer, as overs are not limited to a set number of balls bowled. For instance, if a bowler delivers wides or no balls (for stepping over the crease in his delivery stride or bowling a full toss above waist height), the over can continue indefinitely.
Based on six legal deliveries, however, the most achievable from a single over is typically 36.
This would involve a batsman hitting every ball of the over for six, a feat which has been achieved very rarely in the professional game.
Sir Garfield Sobers, the West Indies legend, was the first to manage it back in 1968 when batting for Nottinghamshire against Glamorgan at Swansea. Malcolm Nash was the unlucky bowler.
In the 51 years since, Ravi Shastri – the India allrounder, Herschelle Gibbs of South Africa (who did it in a World Cup game against the Netherlands), Yuvraj Singh, Worcestershire’s Ross Whiteley and the Afghanistan batsman Hazratullah Zazai (who did so in 2018) have matched Sobers’ remarkable effort.
Of course, with a combination of wides, no balls and other runs, it is possible for a team to score more than 36 in an over.
One such example came in New Zealand in February 1990.
Bert Vance, the former New Zealand international batsman who was never considered a bowler of any kind of ability, was handed the ball during Shell Trophy match between Wellington and Canterbury in Christchurch. He proceeded to bowl a series of no balls, with only one of his first 17 deliveries ending up legal.
The monstrous over also featured six fours and eight sixes as the opposition took 77 off the beleaguered Vance. That story is the oddity, though, and 36 is typically considered to be the maximum.