Here is the full list of all 57 Star Wars Knights of the Old Republic II: The Sith Lords achievements.
Reach Player Level 30
Learn Moving Meditation
Have 30 points in Stealth
Kill all Sith troopers before they can board the Ebon Hawk
Flee Korriban after fighting Sion
Get this by starting the "Trapped" Quest on Korriban.
Loot a body on Korriban
Repair the damaged droid on the Ebon Hawk
Convince Vogga the Hutt to sell fuel to Telos.
Recruit Mira
Beat the champ on Nar Shadaa
Convince the "champ" to lose the game without playing.
Side with the Queen on Onderon
Side with the Settlers at Khoonda
Get the named Lightsaber crystal
Teach the Handmaiden the ways of the Force.
Learn Force Sight
Contruct your first Lightsaber
Gain a Prestige class
Complete the Mandalorian Battle Circle
Recruit the Handmaiden
Complete the Handmaiden Battle Circle
Reach maximum Light Side points
Get your first Dark Side points
Let the Sith destroy the Peragus Asteroids
Dance for Vogga
Get your first Light Side points
Have 30 points in Treat Injury.
Have 30 points in Demolitions.
Have 30 points in Computer Use.
Have 30 points in Repair.
Defeat Nihilus
Collect 10,000 credits
Fill the Party Selection screen
Have Persuasion over 30
Complete the Prologue
Destroy Peragus Astroids
Defeat Sion
Complete the game on the Light Side
Complete the game on the Dark Side
Install HK-47's unique module
Side with Vaklu on Onderon
Recruit Hanharr
Break Hanharr's spirit
Change your mind about siding with the Settlers at Khoonda
Recruit the Disciple
Reach maximum Dark Side points
Win a Pazaak game with a full board
Reduce a companion's Influence to zero.
Acquire all Dark Side Powers.
Acquire all Light Side Powers
Kill all the Jedi masters
Claim Darth Nihilus' mask.
Have your character replace any of the Sith Lords on the main menu screen.
Deduce G0-T0's identity
Learn how to kill Jedi from HK-47
Listen to HK-47's definition of love.