If you're on OSX you can also find it your keychain. Your developer and distribution certificates have your Team ID in them.

Applications -> Utilities -> Keychain Access.

Under the 'login' Keychain, go into the 'Certificates' category.

Scroll to find your development or distribution certificate. They will read:

iPhone Distribution: Team Name (certificate id)

or

iPhone Developer: Team Name (certificate id)

Simply double-click on the item, and the

"Organizational Unit"

is the "Team ID"

Note that this is the only way to find your

"Personal team" ID

You can not find the "Personal team" ID on the Apple web interface.

For example, if you are automating a build from say Unity, during development you'll want it to appear in Xcode as your "Personal team" - this is the only way to get that value.

For personal teams

grep DEVELOPMENT_TEAM MyProject.xcodeproj/project.pbxproj

should give you the team ID

DEVELOPMENT_TEAM = ZU88ND8437;

You can find the Team ID via this link: https://developer.apple.com/membercenter/index.action#accountSummary

Apple has changed the interface.

The team ID could be found via this link: https://developer.apple.com/account/#/membership

There are ways you can check even if you are not a paid user. You can confirm TeamID from Xcode. [Build setting] Displayed on tooltip of development team.

2024-2026

You can get it on the page Apple Developer Account and select from the menu above Membership Details (see 1st screenshot)

Your team ID will be here (see 2nd screenshot)

If you prefer the command line, you can use the command in the terminal in your project directory:

grep DEVELOPMENT_TEAM *.xcodeproj/*.pbxproj -m 1 | sed -E 's/^[[:space:]]+//'

You will get something like this line:

DEVELOPMENT_TEAM = 473A04LG6W;

Other options you can get on the official page Developer Account Help (they made it very convenient).

For a flutter project and personal team.

navigate to below address and search for DEVELOPMENT_TEAM you should find some thing like this DEVELOPMENT_TEAM = 64F9WR9M48

ios/Runner.xcodeproj/project.pbxproj

It's now under Certificates, Identities & Profiles top right you have your name in the first line, and in the second your name again and right to it is the Team ID.

I wanted to get this from the command line (Terminal) so I came up with this bash script.

Update Oct 2024: Script has been slightly updated.

Link to gist

#!/usr/bin/env bash

CODESIGN_CN_STRING='Developer ID Application' #change if necessary to match your certname

#requires openssl@3 from Homebrew
_openssl=$(brew --prefix openssl 2>/dev/null)/bin/openssl
[[ -x $_openssl ]] || { echo "missing openssl, try \`brew install openssl\`"; exit 1; }

#find development cert
csids=$(security find-identity -v -p codesigning | grep -E '[A-F0-9]{40}')
[[ -n $csids ]] || { echo 1>&2 "could not find codesigning identity"; exit 1; }
read -r sha1 cn _ < <(sed -En "s/^.*([A-F0-9]{40}).*$CODESIGN_CN_STRING.*\((.*)\).*$/\1 \2/p" <<<"$csids")
[[ -n $cn && -n $sha1 ]] || { echo 1>&2 "could not find valid development cert"; exit 1; }

#make temp dir
outdir=$(mktemp -d /private/tmp/teamid.XXXXXX)
[[ -n $outdir ]] || { echo "error creating temp dir"; exit 1; }

#export cert
if ! security find-certificate -a -c "$cn" -Z -p >"${outdir}/${cn}.pem"; then
  echo "error exporting cert from Keychain"
  exit 1
fi

#check for hash match
certhash=$(awk -v h="$sha1" '$0 ~ "^SHA-1 hash: " h {print $NF; exit}' "${outdir}/${cn}.pem")
[[ $certhash == "$sha1" ]] || { echo "hash mismatch! ($certhash vs $sha1)"; exit 1; }

#output DEVELOPMENT_TEAM
$_openssl x509 -in "${outdir}/${cn}.pem" -subject -noout |
sed -En 's/.*OU ?= ?([^,]+),.*$/\1/p'

#cleanup
rm -r "${outdir:?}"

to find TeamID from Terminal

grep DEVELOPMENT_TEAM /Users/..../XXX.xcodeproj/project.pbxproj