Jeff Tidball is a game designer who has worked primarily on role-playing games.

Jeff Tidball was a college student when he began working full-time at Atlas Games when the company expanded after the success of On the Edge (1994).^[1]: 254 John Nephew and Tidball were the only staff that Atlas retained after the collectible card game field crashed in 1996.^[1]: 254 Tidball became the Director of Creative Development and soon began developing the next role-playing game from Atlas Games, Ars Magica, which Atlas had acquired from Wizards of the Coast.^[1]: 254 Tidball also became the line developer for Ars Magica,^[1]: 255 and the Feng Shui line developer as well.^[2] Tidball designed Cults Across America (1998) which was one of the board and card game releases from Atlas.^[1]: 257 Tidball left Atlas Games in 2000 to take a Master of Fine Arts film script-writing program available at the University of Southern California.^[1]: 255 Tidball later went to work at Last Unicorn Games, and Tidball and Jess Heinig were the only remaining employees by January 2004 in the Last Unicorn Games role-playing game division of Decipher Games, so Decipher shut down Last Unicorn Games and laid them off.^[1]: 318 Tidball designed the Cthulhu 500 card game for Atlas.^[2] Tidball worked as the line developer for Decipher's The Lord of the Rings Roleplaying Game.^[2] Tidball designed Pieces of Eight (2006), a game by using coins as a game mechanic which Atlas published.^[1]: 259 Will Hindmarch and Tidball later started a small press company called Gameplaywright.^[1]: 260 Tidball subsequently worked as the senior developer and editor for the board and card game departments at Fantasy Flight Games,^[2] before returning to Atlas Games on a contract basis as chief operating officer. He has also continued to write in the roleplaying industry, notably the massive Eternal Lies campaign he wrote with Hindmarch for Pelgrane Press's Trail of Cthulhu RPG.

Tidball lives with his wife and sons in the Twin Cities area.^[2]