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