William Edward "Bill" Maclagan (5 April 1858 – 10 October 1926) was a Scottish international rugby union forward who played club rugby for London Scottish F.C.. Maclagan was one of the longest-serving international rugby players during the early development of the sport, and was awarded 25 caps for Scotland.He played international rugby for thirteen seasons, a Scottish record for sixty years, and led the first official British Isles team on its 1891 tour of South Africa.