Outpacing the opponent by one point can flip a match. Jolly adds 10% Speed and lowers Sp. Attack, which physical attackers don't mind. For Crystal, Tyranitar, Starmie, Arcanine, and others all run Jolly in competitive play. There's no way to set natures in Crystal. You'll lock in Jolly when catching or breeding in Ruby/Sapphire or later.

Jolly raises Speed by 10% and lowers Sp. Attack by 10%. Fast physical attackers that need to outspeed threats. 99 Pokemon competitively run this nature.
#PokemonTierRoleAbility+Spe-SpASpe
1
Tyranitar
Tyranitar
ROCKDARK
APhysical AttackerSand Stream
61+11
95-12
61
2
Starmie
Starmie
WATERPSYCHIC
APhysical AttackerNatural Cure
115+16
100-12
115
3APhysical AttackerIntimidate
95+14
100-12
95
4
Scyther
Scyther
BUGFLYING
APhysical AttackerTechnician
105+15
55-8
105
5
Entei
Entei
FIRE
APhysical AttackerInnerfocus
100+15
90-11
100
6
Mew
Mew
PSYCHIC
ABulky SupportSynchronize
100+15
100-12
100
7
Gyarados
Gyarados
WATERFLYING
APhysical AttackerIntimidate
81+13
60-8
81
8
Scizor
Scizor
BUGSTEEL
APhysical AttackerSwarm
65+11
55-8
65
9
Donphan
Donphan
GROUND
APhysical AttackerSturdy
50+10
60-8
50
10
Hitmontop
Hitmontop
FIGHTING
APhysical AttackerTechnician
70+12
35-6
70
11
Sandslash
Sandslash
GROUND
APhysical AttackerSandrush
65+11
45-7
65
Tyranitar
Tyranitar
ROCK DARK
A
Role
Physical Attacker
Ability
Sand Stream
+Spe
61 +11
Spe
61
Starmie
Starmie
WATER PSYCHIC
A
Role
Physical Attacker
Ability
Natural Cure
+Spe
115 +16
Spe
115
A
Role
Physical Attacker
Ability
Intimidate
+Spe
95 +14
Spe
95
Scyther
Scyther
BUG FLYING
A
Role
Physical Attacker
Ability
Technician
+Spe
105 +15
Spe
105
Entei
Entei
FIRE
A
Role
Physical Attacker
Ability
Innerfocus
+Spe
100 +15
Spe
100
Mew
Mew
PSYCHIC
A
Role
Bulky Support
Ability
Synchronize
+Spe
100 +15
Spe
100
Gyarados
Gyarados
WATER FLYING
A
Role
Physical Attacker
Ability
Intimidate
+Spe
81 +13
Spe
81
Scizor
Scizor
BUG STEEL
A
Role
Physical Attacker
Ability
Swarm
+Spe
65 +11
Spe
65
Donphan
Donphan
GROUND
A
Role
Physical Attacker
Ability
Sturdy
+Spe
50 +10
Spe
50
Hitmontop
Hitmontop
FIGHTING
A
Role
Physical Attacker
Ability
Technician
+Spe
70 +12
Spe
70
Sandslash
Sandslash
GROUND
A
Role
Physical Attacker
Ability
Sandrush
+Spe
65 +11
Spe
65
+10%Speed
-10%Sp. Attack
Flavor Preference
Likes Sweet, dislikes Dry
Competitive Role
Fast physical attackers that need to outspeed threats.
Jolly vs Adamant
Choose Jolly
+Speed / -Sp. Attack
  • Pokemon in contested speed tiers (base 80-110)
  • Sweepers that need to outspeed threats before attacking
  • Pokemon without priority moves or speed-boosting setups
Choose Adamant
+Attack / -Sp. Attack
  • Pokemon with priority moves that bypass speed
  • Dragon Dance / Shift Gear users that fix speed in-game
  • Wallbreakers that need maximum damage output
How to Get
SynchronizeLead with a Jolly Pokemon that has the Synchronize ability. Wild Pokemon will match its nature. (Gen 3+)
BreedingGive the parent with Jolly nature an Everstone. The offspring will inherit it. (100% since Gen 5)
Nature MintUse a Jolly Mint to change stat effects to Jolly. The original nature name stays but stats change. (Gen 8+)
What does the Jolly nature do in Pokemon?
Jolly gives your Pokemon 10% more Speed at the cost of Sp. Attack. That tradeoff works best when the lowered stat isn't part of your moveset. Pokemon with Jolly nature prefer Sweet flavor and dislike Dry.
What are the best Jolly nature Pokemon?
Competitively, Tyranitar, Starmie, Arcanine, and Scyther run Jolly most often. The +Speed boost complements their role, and the -Sp. Attack penalty barely affects their game plan.
Is Jolly a good nature for competitive Pokemon?
For the right Pokemon, Jolly is one of the best natures you can pick. It's one of the most-used natures in competitive formats. Just don't slap it on something that uses Sp. Attack-based moves.
How do I get a Jolly nature Pokemon?
Breeding with an Everstone is the most reliable approach since Gen 5. The parent holding it passes its nature to every offspring. Synchronize works for wild catches. And if you already have the Pokemon, a Jolly Mint from the Battle Tower changes the stat effects to Jolly.
Should I use Jolly or Adamant?
Short answer: Jolly for speed, Adamant for power. There's no universal best. Check your Pokemon's base stats and common threats in the format you're playing to decide which tradeoff is better.