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