John Thewlis senior (30 June 1828 – 29 December 1899) was an English first-class cricketer, active 1862–75, who played for Sheffield and Yorkshire. Thewlis was noted as a right-hand batsman with a full range of strokes.
Thewlis came late into the game and was the second man to emerge from Lascelles Hall, Huddersfield, and play for his home county. The first, Luke Greenwood, became county captain. George Parr, successor to William Clarke in the management of the All-England Eleven, approached him for advice: "Greenwood, we are going to Southampton to play 22 there. Do you know a good batter?" Greenwood replied that, in Thewlis, he did, and so, on nothing more than that brief paean, Parr included him as opening batsman. He was bowled first ball and, as he left the wicket, turned and vowed to the bowler that it would not happen again; nor did it, as Thewlis worked his way to 41 not out in the second innings.
Thewlis went on to enjoy a successful first-class career with his county and elsewhere, scoring 1,548 runs at an average of 15.48. His solitary century came against Surrey, whom he met seventeen times. He also appeared for the All-England Eleven (1862), North of England (1864-1865), England (1864-1868, albeit not at Test level), United England Eleven (1865), the Players (1868) and the United North of England Eleven (1875). With his playing days all but behind him, he umpired at least sixteen first-class matches from 1869 to 1887.