Here is the full list of all 37 Thief achievements. It takes around 40-50 hours to unlock all of the achievements on Windows.
Finished the game with a custom difficulty of 700 points or more
Finished the game without a single kill or knockout
Finished the game on Master difficulty
Reached the final chapter without using the focus ability
Scored an epic 5,000,000 or more in a Challenge Map
Discovered all secret areas
Used 40,000 gold
Completed all collectible sets
Shot a bottle in mid-air with an arrow
Completed 25 optional Thieving Objectives
Picked 100 pockets in a single playthrough
Found all the secret stashes in Moira
Stole all loot and collectibles in a single chapter.
Finished Chapter Eight
Finished the game in 15 hours or more
Finished Chapter Seven
Completed all Basso Jobs in The City
Completed all client jobs in The City
Completed a collectible set
Finished Chapter Six
Picked a pocket and a lock using the focus ability
Discovered 15 secret areas
Finished Chapter Five
Disarmed ten trap mechanisms
Completed 10 optional Thieving Objectives
Finished Chapter Four
Picked a lock with masterful speed
Finished Chapter Three
Killed or knocked out 10 people using the environment
Finished 3 consecutive chapters without taking damage
Finished Chapter Two
Sweet sixteen. Snuff said.
Stole 5 collectibles
Finished Chapter One
Finished a single chapter without alerting anyone
Uncovered Lyegrove's secret
Finished the Prologue