A lot of episodes.
Pilots (2011)
1. Way of the Ninja
2. The Golden Weapon
3. King of Shadows
4. Weapons of Destiny
Season 1: Rise of the Snakes (2011 - 2012)
1. Rise of the Snakes
2. Home
3. Snakebit
4. Never Trust a Snake
5. Can of Worms
6. The Snake King
7. Tick Tock
8. Once Bitten, Twice Shy
9. The Royal Blacksmiths
10. The Green Ninja
11. All of Nothing
12. The Rise of the Great Devourer
13. Day of the Great Devourer
Season 2: The Final Battle (2012 - 2013)
1. Darkness Shall Rise
2. Pirates Vs. Ninja
3. Double Trouble
4. Ninjabal Run
5. Child's Play
6. Wrong Place, Wrong Time
7. The Stone Army
8. The Day Ninjago Stood Still
9. The Last Voyage
10. Island of Darkness
11. The Last Hope
12. Return of the Overlord
13. Rise of the Spinjitzu Master
Season 3: Rebooted (2014)
1. The Surge
2. The Art of the Silent Fist
3. Blackout
4. The Curse of the Golden Master
5. Enter the Digiverse
6. Codename: Arcturus
7. The Void
8. The Titanium Ninja
Season 4: The Tournament of Elements (2015)
1. The Invitation
2. Only One Can Remain
3. Versus
4. Ninja Roll
5. Spy for a Spy (Upcoming)
6. Spellbound (Upcoming)