diff --git a/CHANGELOG b/CHANGELOG
index a8d2a7476e..f539408f14 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -37,6 +37,7 @@ git-annex (10.20230408) UNRELEASED; urgency=medium
     of core.sharedRepository and umask.
   * initremote: Avoid creating a remote that is not encrypted when gpg is
     broken.
+  * unannex: Support --json and --json-error-messages.
 
  -- Joey Hess <id@joeyh.name>  Sat, 08 Apr 2023 13:57:18 -0400
 
diff --git a/Command/Unannex.hs b/Command/Unannex.hs
index 799a31ef8d..c6cb70793a 100644
--- a/Command/Unannex.hs
+++ b/Command/Unannex.hs
@@ -22,7 +22,7 @@ import qualified Utility.RawFilePath as R
 import System.PosixCompat.Files (linkCount)
 
 cmd :: Command
-cmd = withAnnexOptions [annexedMatchingOptions] $
+cmd = withAnnexOptions [jsonOptions, annexedMatchingOptions] $
 	command "unannex" SectionUtility
 		"undo accidental add command"
 		paramPaths (withParams seek)
diff --git a/doc/git-annex-unannex.mdwn b/doc/git-annex-unannex.mdwn
index 3b6c7d263d..157318de2c 100644
--- a/doc/git-annex-unannex.mdwn
+++ b/doc/git-annex-unannex.mdwn
@@ -28,6 +28,16 @@ case you should use `git annex drop` instead, and you can also
   But use --fast mode with caution, because editing the file will
   change the content in the annex.
 
+* `--json`
+
+  Enable JSON output. This is intended to be parsed by programs that use
+  git-annex. Each line of output is a JSON object.
+
+* `--json-error-messages`
+
+  Messages that would normally be output to standard error are included in
+  the JSON instead.
+
 * file matching options
 
   The [[git-annex-matching-options]](1)
diff --git a/doc/todo/--json_for_unannex__and_ideally_any_other_command_.mdwn b/doc/todo/--json_for_unannex__and_ideally_any_other_command_.mdwn
index 2f071d93fb..b4c17a4783 100644
--- a/doc/todo/--json_for_unannex__and_ideally_any_other_command_.mdwn
+++ b/doc/todo/--json_for_unannex__and_ideally_any_other_command_.mdwn
@@ -2,3 +2,103 @@ While looking for various spots where `core.quotepath=true` is now treated by gi
 
 [[!meta author=yoh]]
 [[!tag projects/repronim]]
+
+These commands have been updated to support --json:
+
+* git-annex-unannex
+
+Provisional list of commands that don't support --json and maybe should:
+
+(Feel free to reorder things to the top)
+ 
+* git-annex-addunused
+* git-annex-adjust
+* git-annex-assistant
+* git-annex-backends
+* git-annex-benchmark
+* git-annex-calckey
+* git-annex-checkpresentkey
+* git-annex-common-options
+* git-annex-config
+* git-annex-configremote
+* git-annex-contentlocation
+* git-annex-dead
+* git-annex-describe
+* git-annex-diffdriver
+* git-annex-direct
+* git-annex-dropunused
+* git-annex-edit
+* git-annex-enable-tor
+* git-annex-enableremote
+* git-annex-expire
+* git-annex-filter-branch
+* git-annex-filter-process
+* git-annex-findref
+* git-annex-fix
+* git-annex-forget
+* git-annex-fuzztest
+* git-annex-group
+* git-annex-groupwanted
+* git-annex-importfeed
+* git-annex-indirect
+* git-annex-init
+* git-annex-initremote
+* git-annex-inprogress
+* git-annex-list
+* git-annex-log
+* git-annex-lookupkey
+* git-annex-map
+* git-annex-matchexpression
+* git-annex-matching-expression
+* git-annex-matching-options
+* git-annex-merge
+* git-annex-migrate
+* git-annex-mincopies
+* git-annex-multicast
+* git-annex-numcopies
+* git-annex-p2p
+* git-annex-post-receive
+* git-annex-pre-commit
+* git-annex-preferred-content
+* git-annex-proxy
+* git-annex-readpresentkey
+* git-annex-reinit
+* git-annex-reinject
+* git-annex-rekey
+* git-annex-remotedaemon
+* git-annex-renameremote
+* git-annex-repair
+* git-annex-required
+* git-annex-resolvemerge
+* git-annex-restage
+* git-annex-rmurl
+* git-annex-schedule
+* git-annex-semitrust
+* git-annex-setkey
+* git-annex-setpresentkey
+* git-annex-shell
+* git-annex-smudge
+* git-annex-sync
+* git-annex-test
+* git-annex-testremote
+* git-annex-transferkey
+* git-annex-transferkeys
+* git-annex-transferrer
+* git-annex-trust
+* git-annex-undo
+* git-annex-ungroup
+* git-annex-uninit
+* git-annex-untrust
+* git-annex-unused
+* git-annex-upgrade
+* git-annex-vadd
+* git-annex-vcycle
+* git-annex-version
+* git-annex-vfilter
+* git-annex-vicfg
+* git-annex-view
+* git-annex-vpop
+* git-annex-wanted
+* git-annex-watch
+* git-annex-webapp
+* git-annex-whereused
diff --git a/doc/todo/--json_for_unannex__and_ideally_any_other_command_/comment_1_9cc7829b4742f21077a27caad7ae638e._comment b/doc/todo/--json_for_unannex__and_ideally_any_other_command_/comment_1_9cc7829b4742f21077a27caad7ae638e._comment
new file mode 100644
index 0000000000..8ec161dbc3
--- /dev/null
+++ b/doc/todo/--json_for_unannex__and_ideally_any_other_command_/comment_1_9cc7829b4742f21077a27caad7ae638e._comment
@@ -0,0 +1,17 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 1"""
+ date="2023-05-03T19:33:50Z"
+ content="""
+I agree generally, anything that is not already
+explicitly machine parseable should support --json
+(and --json-error-options will be available for free once that's added)
+
+I'd exclude things like `git-annex find` which have
+--format that can be used similarly; and a separate json
+output would not be very useful for find anyway probably?
+
+I've added a list of commands that currently don't support --json above.
+
+Did unannex already, as it was trivial.
+"""]]