- Gad zooks
- Game is afoot
- Game is up
- Game of two halves
- Gee-up
- Gee whiz
- Generation X
- Genius is one percent inspiration and 99 percent perspiration
- Get a word in edgeways
- Get down to brass tacks
- Get medieval
- Get off on the wrong foot
- Get off your high horse
- Get on my wick
- Get one's dander up
- Get over it
- Get the pip
- Get the sack
- Get the upper hand
- Get thee behind me Satan
- Get underway
- Get used to it
- Get your dander up
- Get your goat
- Giddy aunt
- Giddy goat
- Gild the lily
- Gilt off the gingerbread
- Ginned up
- Ginger
- Ginger up
- Give a man a fish and you will feed him for a day
- Give a wide berth
- Give no quarter
- Give the Devil his due
- Give up the ghost
- Giving me gyp
- Glass ceiling
- Gloom and doom
- Go and boil your head
- Go berserk
- Go by the board
- Go by the book
- Go Dolally
- Go-faster
- Go for a burton
- Go haywire
- Go like the clappers
- Go off half-cocked
- Go out on a limb
- Go postal
- Go over like a lead balloon
- Going to hell in a handbasket
- Go pound sand
- Go the whole hog
- Go to pot
- Go to the dogs
- Go to the foot of our stairs
- Go to the mattresses
- Go whole hog
- God bless you!
- God is dead
- God rest ye merry, gentlemen
- God rot them
- Godfrey Daniel
- Going for a burton
- Golden key can open any door
- GOLF – Gentlemen only, ladies forbidden
- Gone for a burton
- Good as gold
- Good hiding
- Good in parts
- Good man is hard to find
- Good measure
- Good men and true
- Good money after bad
- Good riddance
- Good Samaritan
- Goodnight Vienna
- Goody, goody gumdrops
- Goody two-shoes
- Gordon Bennett
- Got my mojo working
- Grace of God
- grain of salt
- Grand slam
- Grandfather clock
- Granny dumping
- Grasp the nettle
- Grass is always greener on the other side of the fence
- Grass up
- Graveyard shift
- Greased lightning
- Great balls of fire
- Great minds think alike
- Great oaks from little acorns grow
- Great unwashed
- Greek to me
- Green eyed monster
- Gregory Peck
- Gridlock
- Grind to a halt
- Grinning like a Cheshire cat
- Grist to the mill
- Grose
- Grub Street
- Gry – Words ending in
- Guinea pig
- Gung ho
- Gussied-up
- Guts for garters