There are 50 achievements with a total of 1000 gamerscore.
| Unlockable: | How to unlock: |
| He's Got The Jack (5 points) | Mission 5: Jack 6 Covenant Vehicles |
| Backscratcher (10 points) | Complete any Campaign Mission in Co-op Mode |
| Sweet Naptime (5 points) | Mission 9: Put every Colony in Hibernation Mode at the same time |
| Empire Builder (5 points) | Win a game in every Skirmish Game Mode |
| 2 Bugs are Better Than 1 (10 points) | Win a Skirmish Game with Dual Scarabs |
| OMG BFF FTW (40 points) | Complete entire Campaign in Co-op Mode |
| Detour the Great Journey (50 points) | Complete the Campaign on Legendary Difficulty |
| Didn't Get To Second Base (5 points) | Mission 14: Don't claim an extra base |
| Momma's Boy (5 points) | Get a Gold Medal on any mission |
| The Procrastinator (5 points) | Mission 10: Disrupt all Tractor Beams |
| Adjudicate the Arbiter (30 points) | Complete the Campaign on Heroic Difficulty |
| Covenant | Mission 3: Kill at least 5 Covenant Units with the Bridge |
| Handy with Tools (5 points) | Mission 12: Repair the Power Core in less than 4 minutes |
| Gallivant around the Galaxy (25 points) | Win a game on every Skirmish Map |
| Titan (15 points) | Get 20,000 points in any Skirmish Game |
| Everything's Better with Bacon (5 points) | Mission 1: Ram 50 Grunts with Warthogs |
| Rhino Hugger (5 points) | Mission 6: Successfully protect every Rhino |
| Epic Grinder (40 points) | Obtain a Lifetime Campaign Score over 1,000,000 |
| Own Worst Enemy (20 points) | Get a Gold Medal with all Debuff Skulls Active |
| Penny Pincher (10 points) | Get a winning High Score with 10 or less Squads against the Heroic AI |
| Basically Naive (10 points) | Obtain the Recruit Rank on Xbox LIVE |
| Crushed Colors (10 points) | Improve your Score in any Campaign Mission |
| Playin' the Field (15 points) | Win a Skirmish Game with every Leader |
| My Virtual Friends Love Me (10 points) | Win a 3v3 Skirmish game with 2 AI Allies |
| Battened Down the Hatches (5 points) | Mission 11: Save all the Airlocks |
| So Lonely at the Top (20 points) | Win and have the Highest Score in a Matchmade Skirmish Game on Xbox LIVE |
| Big Al's Scooter (10 points) | Win a Heroic Skirmish Game against the AI in under 10 minutes |
| Beaming with Pride (5 points) | Mission 13: Destroy 25 units with the Scarab |
| Running the Show (50 points) | Obtain the General Rank on Xbox LIVE |
| Halo Historian (40 points) | Unlock All Timeline Events |
| Endless Fun (5 points) | Mission 2: Destroy every Methane Tank |
| 24 Hours of Quality (20 points) | Play Halo Wars for at least 24 Total Hours |
| Halo Academic (15 points) | Unlock 20 Timeline Events |
| Mr. Punctual (15 points) | Finish all missions under Par Time on Heroic difficulty |
| Alas, Poor Andrew Thomas (5 points) | Collect your first Skull |
| Ramblin' Man (5 points) | Mission 8: Use Elephants to train 100 Infantry |
| Graverobber (30 points) | Collect all Skulls |
| Micro Manager (5 points) | Mission 7: Do not destroy any Power Node |
| N00b n0 M0r3 (10 points) | Win a Matchmade Skirmish Game on Xbox LIVE |
| Officer on Deck (30 points) | Obtain the Lieutenant Rank on Xbox LIVE |
| Walk-Off Winner (30 points) | Use one of the 6 Major Leader Powers to destroy an enemy's last unit |
| Thinkin' about My Doorbell (5 points) | Mission 15: Open the Doors in order |
| The Real Winner (5 points) | Mission 4: Save Adam |
| Wall of Recognition (30 points) | Get a Gold Medal on every Campaign Mission |
| Ready for the Sequel (75 points) | 100% Completion |
| Secret Achievement (10 points) | Continue playing to unlock this secret achievement. |
| Secret Achievement (40 points) | Continue playing to unlock this secret achievement. |
| Secret Achievement (50 points) | Continue playing to unlock this secret achievement. |
| Secret Achievement (70 points) | Continue playing to unlock this secret achievement. |
| Secret Achievement (70 points) | Continue playing to unlock this secret achievement. |
