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