Psychic is learned by 88 species by level, 239 by machine, 2 by tutor and 1 by egg

Effect, in PokéAPI's words

“Has a chance to lower the target’s Special Defense by one stage.”

Who learns it

239 species in all, 5 of 25 games shown

Scarlet and Violet: 174 species

Species	Method	Level
Gallade	Level up, Machine	1
Ralts	Level up, Machine	30
Deoxys	Level up, Machine	31
Metang	Level up, Machine	34
Metagross	Level up, Machine	34
Indeedee	Level up, Machine	35
Slowpoke	Level up, Machine	36
Slowbro	Level up, Machine	36
Spinarak	Level up, Machine	36
Slowking	Level up, Machine	36
Gothita	Level up, Machine	36
Solosis	Level up, Machine	36
Drowzee	Level up, Machine	37
Kirlia	Level up, Machine	38
Espeon	Level up, Machine	40
Gothitelle	Level up, Machine	40
Duosion	Level up, Machine	40
Reuniclus	Level up, Machine	40
Hatenna	Level up, Machine	40
Munkidori	Level up, Machine	40
Ariados	Level up, Machine	41
Fennekin	Level up, Machine	41
Hypno	Level up, Machine	42
Gardevoir	Level up, Machine	42
Jirachi	Level up, Machine	42
Spoink	Level up, Machine	44
Hattrem	Level up, Machine	44
Oranguru	Level up, Machine	45
Hatterene	Level up, Machine	46
Venonat	Level up, Machine	47
Mewtwo	Level up, Machine	48
Uxie	Level up, Machine	49
Mesprit	Level up, Machine	49
Azelf	Level up, Machine	49
Braixen	Level up, Machine	49
Lunala	Level up, Machine	49
Espathra	Level up, Machine	49
Girafarig	Level up, Machine	50
Rabsca	Level up, Machine	50
Farigiraf	Level up, Machine	50
Grumpig	Level up, Machine	52
Cresselia	Level up, Machine	54
Meowstic	Level up, Machine	54
Venomoth	Level up, Machine	55
Calyrex	Level up, Machine	56
Meloetta	Level up, Machine	57
Delphox	Level up, Machine	57
Latias	Level up, Machine	60
Latios	Level up, Machine	60
Hoopa	Level up, Machine	75
Mew	Level up, Machine	100
Clefairy	Machine
Clefable	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Psyduck	Machine
Golduck	Machine
Poliwag	Machine
Poliwhirl	Machine
Poliwrath	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Exeggcute	Machine
Exeggutor	Machine
Chansey	Machine
Electabuzz	Machine
Magmar	Machine
Lapras	Machine
Porygon	Machine
Hoothoot	Machine
Noctowl	Machine
Cleffa	Machine
Igglybuff	Machine
Politoed	Machine
Yanma	Machine
Umbreon	Machine
Murkrow	Machine
Misdreavus	Machine
Porygon2	Machine
Stantler	Machine
Elekid	Machine
Magby	Machine
Blissey	Machine
Lugia	Machine
Ho-Oh	Machine
Sableye	Machine
Meditite	Machine
Medicham	Machine
Shuppet	Machine
Banette	Machine
Duskull	Machine
Dusclops	Machine
Chimecho	Machine
Drifloon	Machine
Drifblim	Machine
Mismagius	Machine
Honchkrow	Machine
Chingling	Machine
Bronzor	Machine
Bronzong	Machine
Happiny	Machine
Spiritomb	Machine
Lucario	Machine
Electivire	Machine
Magmortar	Machine
Yanmega	Machine
Porygon-Z	Machine
Dusknoir	Machine
Froslass	Machine
Giratina	Machine
Manaphy	Machine
Darkrai	Machine
Shaymin	Machine
Arceus	Machine
Whimsicott	Machine
Zoroark	Machine
Gothorita	Machine
Alomomola	Machine
Litwick	Machine
Lampent	Machine
Chandelure	Machine
Golett	Machine
Golurk	Machine
Larvesta	Machine
Volcarona	Machine
Tornadus	Machine
Thundurus	Machine
Reshiram	Machine
Zekrom	Machine
Landorus	Machine
Kyurem	Machine
Vivillon	Machine
Flabébé	Machine
Floette	Machine
Florges	Machine
Espurr	Machine
Inkay	Machine
Malamar	Machine
Sylveon	Machine
Carbink	Machine
Klefki	Machine
Phantump	Machine
Trevenant	Machine
Noibat	Machine
Noivern	Machine
Diancie	Machine
Primarina	Machine
Cutiefly	Machine
Ribombee	Machine
Sandygast	Machine
Palossand	Machine
Minior	Machine
Mimikyu	Machine
Bruxish	Machine
Solgaleo	Machine
Necrozma	Machine
Magearna	Machine
Sinistea	Machine
Polteageist	Machine
Alcremie	Machine
Spectrier	Machine
Wyrdeer	Machine
Enamorus	Machine
Armarouge	Machine
Flittle	Machine
Veluza	Machine
Scream Tail	Machine
Iron Moth	Machine
Gholdengo	Machine
Chi-Yu	Machine
Iron Valiant	Machine
Iron Boulder	Machine
Iron Crown	Machine

Legends Arceus: 20 species

Species	Method	Level
Espeon	Level up	25
Clefairy	Level up	29
Clefable	Level up	29
Cleffa	Level up	29
Mr. Mime	Level up	34
Ralts	Level up	34
Kirlia	Level up	34
Gardevoir	Level up	34
Wormadam	Level up, Tutor	34
Mothim	Level up	34
Mime Jr.	Level up	34
Gallade	Level up	34
Cresselia	Level up	36
Kadabra	Level up	43
Alakazam	Level up	43
Duskull	Level up	43
Dusclops	Level up	43
Dusknoir	Level up	43
Darkrai	Level up	46
Shaymin	Tutor

Brilliant Diamond and Shining Pearl: 120 species

Species	Method	Level
Starmie	Level up, Machine	1
Gallade	Level up, Machine	1
Ralts	Level up, Machine	30
Lunatone	Level up, Machine	30
Solrock	Level up, Machine	30
Smoochum	Level up, Machine	32
Jynx	Level up, Machine	34
Gorebyss	Level up, Machine	34
Metang	Level up, Machine	34
Metagross	Level up, Machine	34
Kadabra	Level up, Machine	35
Alakazam	Level up, Machine	35
Natu	Level up, Machine	35
Slowpoke	Level up, Machine	36
Slowbro	Level up, Machine	36
Slowking	Level up, Machine	36
Kirlia	Level up, Machine	38
Staryu	Level up, Machine	40
Spinarak	Level up, Machine	40
Espeon	Level up, Machine	40
Xatu	Level up, Machine	41
Gardevoir	Level up, Machine	42
Jirachi	Level up, Machine	42
Spoink	Level up, Machine	44
Wormadam	Level up, Machine	44
Mothim	Level up, Machine	44
Ariados	Level up, Machine	46
Venonat	Level up, Machine	47
Mr. Mime	Level up, Machine	48
Mewtwo	Level up, Machine	48
Mime Jr.	Level up, Machine	48
Drowzee	Level up, Machine	49
Hypno	Level up, Machine	49
Uxie	Level up, Machine	49
Mesprit	Level up, Machine	49
Azelf	Level up, Machine	49
Girafarig	Level up, Machine	50
Grumpig	Level up, Machine	52
Chimecho	Level up, Machine	52
Cresselia	Level up, Machine	54
Venomoth	Level up, Machine	55
Latias	Level up, Machine	60
Latios	Level up, Machine	60
Mew	Level up, Machine	100
Butterfree	Machine
Clefairy	Machine
Clefable	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Psyduck	Machine
Golduck	Machine
Poliwag	Machine
Poliwhirl	Machine
Poliwrath	Machine
Abra	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Exeggcute	Machine
Exeggutor	Machine
Chansey	Machine
Electabuzz	Machine
Magmar	Machine
Lapras	Machine
Porygon	Machine
Snorlax	Machine
Hoothoot	Machine
Noctowl	Machine
Cleffa	Machine
Igglybuff	Machine
Togepi	Machine
Togetic	Machine
Politoed	Machine
Yanma	Machine
Umbreon	Machine
Murkrow	Machine
Misdreavus	Machine
Corsola	Machine
Remoraid	Machine
Octillery	Machine
Porygon2	Machine
Stantler	Machine
Elekid	Machine
Magby	Machine
Blissey	Machine
Lugia	Machine
Ho-Oh	Machine
Celebi	Machine
Beautifly	Machine
Dustox	Machine
Sableye	Machine
Meditite	Machine
Medicham	Machine
Spinda	Machine
Baltoy	Machine
Claydol	Machine
Shuppet	Machine
Banette	Machine
Duskull	Machine
Dusclops	Machine
Drifloon	Machine
Drifblim	Machine
Mismagius	Machine
Honchkrow	Machine
Chingling	Machine
Bronzor	Machine
Bronzong	Machine
Happiny	Machine
Spiritomb	Machine
Munchlax	Machine
Lucario	Machine
Electivire	Machine
Magmortar	Machine
Togekiss	Machine
Yanmega	Machine
Porygon-Z	Machine
Dusknoir	Machine
Froslass	Machine
Giratina	Machine
Manaphy	Machine

Sword and Shield: 174 species

Species	Method	Level
Starmie	Level up, Machine	1
Gallade	Level up, Machine	1
Musharna	Level up, Machine	1
Spritzee	Level up, Machine	27
Aromatisse	Level up, Machine	27
Ralts	Level up, Machine	30
Lunatone	Level up, Machine	30
Solrock	Level up, Machine	30
Smoochum	Level up, Machine	32
Jynx	Level up, Machine	34
Metang	Level up, Machine	34
Metagross	Level up, Machine	34
Kadabra	Level up, Machine	35
Alakazam	Level up, Machine	35
Natu	Level up, Machine	35
Indeedee	Level up, Machine	35
Slowpoke	Level up, Machine	36
Slowbro	Level up, Machine	36
Slowking	Level up, Machine	36
Munna	Level up, Machine	36
Gothita	Level up, Machine	36
Solosis	Level up, Machine	36
Orbeetle	Level up, Machine	36
Kirlia	Level up, Machine	38
Staryu	Level up, Machine	40
Espeon	Level up, Machine	40
Woobat	Level up, Machine	40
Swoobat	Level up, Machine	40
Sigilyph	Level up, Machine	40
Gothorita	Level up, Machine	40
Gothitelle	Level up, Machine	40
Duosion	Level up, Machine	40
Reuniclus	Level up, Machine	40
Hatenna	Level up, Machine	40
Xatu	Level up, Machine	41
Gardevoir	Level up, Machine	42
Jirachi	Level up, Machine	42
Hattrem	Level up, Machine	44
Yveltal	Level up, Machine	45
Oranguru	Level up, Machine	45
Hatterene	Level up, Machine	46
Mr. Mime	Level up, Machine	48
Mewtwo	Level up, Machine	48
Mime Jr.	Level up, Machine	48
Mr. Rime	Level up, Machine	48
Uxie	Level up, Machine	49
Mesprit	Level up, Machine	49
Azelf	Level up, Machine	49
Cresselia	Level up, Machine	54
Meowstic	Level up, Machine	54
Calyrex	Level up, Machine	56
Latias	Level up, Machine	60
Latios	Level up, Machine	60
Elgyem	Level up, Machine	60
Beheeyem	Level up, Machine	68
Mew	Level up, Machine	100
Butterfree	Machine
Clefairy	Machine
Clefable	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Psyduck	Machine
Golduck	Machine
Poliwag	Machine
Poliwhirl	Machine
Poliwrath	Machine
Abra	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Exeggcute	Machine
Exeggutor	Machine
Chansey	Machine
Electabuzz	Machine
Magmar	Machine
Lapras	Machine
Porygon	Machine
Snorlax	Machine
Hoothoot	Machine
Noctowl	Machine
Cleffa	Machine
Igglybuff	Machine
Togepi	Machine
Togetic	Machine
Politoed	Machine
Umbreon	Machine
Corsola	Machine
Remoraid	Machine
Octillery	Machine
Porygon2	Machine
Elekid	Machine
Magby	Machine
Blissey	Machine
Lugia	Machine
Ho-Oh	Machine
Celebi	Machine
Sableye	Machine
Baltoy	Machine
Claydol	Machine
Duskull	Machine
Dusclops	Machine
Drifloon	Machine
Drifblim	Machine
Bronzor	Machine
Bronzong	Machine
Happiny	Machine
Spiritomb	Machine
Munchlax	Machine
Lucario	Machine
Electivire	Machine
Magmortar	Machine
Togekiss	Machine
Porygon-Z	Machine
Dusknoir	Machine
Froslass	Machine
Giratina	Machine
Victini	Machine
Audino	Machine
Whimsicott	Machine
Darmanitan	Machine
Yamask	Machine
Cofagrigus	Machine
Garbodor	Machine
Frillish	Machine
Jellicent	Machine
Litwick	Machine
Lampent	Machine
Chandelure	Machine
Golett	Machine
Golurk	Machine
Larvesta	Machine
Volcarona	Machine
Tornadus	Machine
Thundurus	Machine
Reshiram	Machine
Zekrom	Machine
Landorus	Machine
Kyurem	Machine
Genesect	Machine
Espurr	Machine
Swirlix	Machine
Slurpuff	Machine
Inkay	Machine
Malamar	Machine
Aurorus	Machine
Carbink	Machine
Klefki	Machine
Phantump	Machine
Trevenant	Machine
Pumpkaboo	Machine
Gourgeist	Machine
Noibat	Machine
Noivern	Machine
Xerneas	Machine
Diancie	Machine
Primarina	Machine
Cutiefly	Machine
Ribombee	Machine
Sandygast	Machine
Palossand	Machine
Mimikyu	Machine
Tapu Lele	Machine
Solgaleo	Machine
Lunala	Machine
Nihilego	Machine
Necrozma	Machine
Blacephalon	Machine
Dottler	Machine
Thievul	Machine
Sinistea	Machine
Polteageist	Machine
Cursola	Machine
Runerigus	Machine
Alcremie	Machine

Let's Go Pikachu and Let's Go Eevee: 36 species

Species	Method	Level
Drowzee	Level up, Machine	31
Venonat	Level up, Machine	32
Hypno	Level up, Machine	36
Staryu	Level up, Machine	36
Venomoth	Level up, Machine	37
Jynx	Level up, Machine	40
Slowpoke	Level up, Machine	42
Kadabra	Level up, Machine	45
Alakazam	Level up, Machine	45
Mr. Mime	Level up, Machine	46
Slowbro	Level up, Machine	49
Mewtwo	Level up, Machine	66
Mew	Level up, Machine	77
Butterfree	Machine
Clefairy	Machine
Clefable	Machine
Jigglypuff	Machine
Wigglytuff	Machine
Psyduck	Machine
Golduck	Machine
Poliwag	Machine
Poliwhirl	Machine
Poliwrath	Machine
Abra	Machine
Gastly	Machine
Haunter	Machine
Gengar	Machine
Exeggcute	Machine
Exeggutor	Machine
Chansey	Machine
Starmie	Machine
Electabuzz	Machine
Magmar	Machine
Lapras	Machine
Porygon	Machine
Snorlax	Machine

Changed over time

One change since Generation I

1. Through Gen IEffect chance 30%10% from Gold and Silver, Generation II