Update 2016: with git 2.8 (March 2016), you can simply use:

git config --list --show-origin

And with Git 2.26 (Q1 2020), you can add a --show-scope option

git config --list --show-origin --show-scope

You will see which config is set where.
See "Where do the settings in my Git configuration come from?"

As Stevoisiak points out in the comments,

it will work with non-standard install locations. (i.e. Git Portable)

(like the latest PortableGit-2.14.2-64-bit.7z.exe, which can be uncompressed anywhere you want)

Original answer (2010)

From the docs:

--global

For writing options: write to global ~/.gitconfig file rather than the repository .git/config.

Since you're using Git for Windows, it may not be clear what location this corresponds to. But if you look at etc/profile (in C:\Program Files\Git), you'll see:

HOME="$HOMEDRIVE$HOMEPATH"

Meaning:

C:\Users\MyLogin

(on Windows 7)

That means the file is in C:\Users\MyLogin\.gitconfig for Git in Windows 7.

On *nixes, it's in ~/.gitconfig. Is there a corresponding file in your home?

On Windows you can type in git bash

notepad ~/.gitconfig

The paths for msysgit are:

Windows XP -C:\Documents and Settings\<user_name>\.gitconfig

Windows Vista+ C:\Users\<user_name>\.gitconfig

When is the global .gitconfig file created?

First off, git doesn't automatically create the global config file (.gitconfig) during its installation. The file is not created until it is written to for the first time. If you have never set a system variable, it will not be on your file system. I'm guessing that might be the source of the problem.

One way to ask Git to create it is to request an edit. Doing so will force the file's creation.

git config --global --edit

If you monitor the user's home folder when you issue this command, you will see the .gitconfig file magically appear.

Where is git configuration stored?

Here's a quick rundown of the the name and location of the configuration files associated with the three Git scopes, namely system, global and local:

• System Git configuration: File named gitconfig located in -git-install-location-/ming<32>/etc
• Global Git configuraiton: File named .gitconfig located in the user's home folder (C:\Users\git user)
• Local Git configuration: File named config in the .git folder of the local repo

Of course, seeing is believing, so here's an image showing each file and each location. I pulled the image from an article I wrote on the topic.

Windows Git configuration file locations (TheServerSide.com)

As @MatrixFrog pointed out in their comment, if the goal is to edit the config, you might want to run:

git config --global --edit

This command will open the config file (in this case, the --global one) in the editor of choice, and await for the file to be closed (just like during git rebase -i).

Just completely agree with @cameron-mckenzie's answer here on this page, above about When is the global .gitconfig file created? (this clearly applies in case of every OS). Rest of his answer deals with Win7 systems.

In Win10 systems too, the .gitconfig global file would create for the very first time only when you tend to set user.name & user.email system variables via windows command-prompt.
As soon as it's set, the .gitconfig file would get created in %USERPROFILE% dir.

Below command works for Win & MacOS, both

So, let's suppose if .gitconfig file already exists. You can know its location via Command-prompt/Gitbash/Terminal by :

git config --global --list --show-origin

I think it is important to post this quote:

Git for Windows supports four levels of configuration. At the lowest level is the machine specific configuration settings known as "portable" and lives a "%ProgramData%\Git\config". One priority level us the installation specific configuration settings known as "system", which live at "\mingw64\etc\gitconfig". Both of these configuration file, generally require elevated privileges to modify.

Starting with the use specific values known as "global" configuration, which can be found at "%UserProfile%.gitconfig", we find the "user editable" configuration files. The highest priority configuration settings are in the "local" configuration, which can usually be found at ".git\config".

It see the recommendation in the blog linked is to modify the "system" or "installation" specific configuration settings, which is fine but users should expect that other installations of Git would not absorb said settings. If you want machine wide settings, use the "portable" configuration file, otherwise choose the "global" or "local" configuration files.

Hopefully, people find this information useful.

source

.gitconfig file location

macOS testing OK

global

# global config
$ cd ~/.gitconfig

# view global config
$ git config --global -l

local

# local config
$ cd .git/config

# view local config
$ git config -l

maybe a bonus for you：Vim or VSCode for edit git config

# open config with Vim

# global config
$ vim ~/.gitconfig

# local config
$ vim .git/config


# open config with VSCode

# global config
$ code ~/.gitconfig

# local config
$ code .git/config

I had installed my Git in: C:\Users\_myuserfolder_\AppData\Local\Programs\Git

git help config

Files section have a detailed description.