diff --git a/cli/args/flags.rs b/cli/args/flags.rs
index cdeaa1b335682c..99db9428138c01 100644
--- a/cli/args/flags.rs
+++ b/cli/args/flags.rs
@@ -477,10 +477,21 @@ pub enum DenoSubcommand {
   Help(HelpFlags),
 }
 
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub enum OutdatedOutputFmt {
+  Table,
+  Json,
+}
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub enum OutdatedKind {
-  Update { latest: bool },
-  PrintOutdated { compatible: bool },
+  Update {
+    latest: bool,
+  },
+  PrintOutdated {
+    compatible: bool,
+    output_fmt: OutdatedOutputFmt,
+  },
 }
 
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -2725,7 +2736,13 @@ Specific version requirements to update to can be specified:
           .long("recursive")
           .short('r')
           .action(ArgAction::SetTrue)
-          .help("include all workspace members"),
+          .help("Include all workspace members"),
+      )
+      .arg(
+        Arg::new("json")
+          .long("json")
+          .action(ArgAction::SetTrue)
+          .help("Output outdated packages in JSON format")
       )
   })
 }
@@ -4495,7 +4512,16 @@ fn outdated_parse(
     OutdatedKind::Update { latest }
   } else {
     let compatible = matches.get_flag("compatible");
-    OutdatedKind::PrintOutdated { compatible }
+    let json = matches.get_flag("json");
+    let output_fmt = if json {
+      OutdatedOutputFmt::Json
+    } else {
+      OutdatedOutputFmt::Table
+    };
+    OutdatedKind::PrintOutdated {
+      compatible,
+      output_fmt,
+    }
   };
   flags.subcommand = DenoSubcommand::Outdated(OutdatedFlags {
     filters,
@@ -11641,7 +11667,21 @@ Usage: deno repl [OPTIONS] [-- [ARGS]...]\n"
         svec![],
         OutdatedFlags {
           filters: vec![],
-          kind: OutdatedKind::PrintOutdated { compatible: false },
+          kind: OutdatedKind::PrintOutdated {
+            compatible: false,
+            output_fmt: OutdatedOutputFmt::Table,
+          },
+          recursive: false,
+        },
+      ),
+      (
+        svec!["--json"],
+        OutdatedFlags {
+          filters: vec![],
+          kind: OutdatedKind::PrintOutdated {
+            compatible: false,
+            output_fmt: OutdatedOutputFmt::Json,
+          },
           recursive: false,
         },
       ),
@@ -11649,7 +11689,10 @@ Usage: deno repl [OPTIONS] [-- [ARGS]...]\n"
         svec!["--recursive"],
         OutdatedFlags {
           filters: vec![],
-          kind: OutdatedKind::PrintOutdated { compatible: false },
+          kind: OutdatedKind::PrintOutdated {
+            compatible: false,
+            output_fmt: OutdatedOutputFmt::Table,
+          },
           recursive: true,
         },
       ),
@@ -11657,7 +11700,10 @@ Usage: deno repl [OPTIONS] [-- [ARGS]...]\n"
         svec!["--recursive", "--compatible"],
         OutdatedFlags {
           filters: vec![],
-          kind: OutdatedKind::PrintOutdated { compatible: true },
+          kind: OutdatedKind::PrintOutdated {
+            compatible: true,
+            output_fmt: OutdatedOutputFmt::Table,
+          },
           recursive: true,
         },
       ),
@@ -11697,7 +11743,10 @@ Usage: deno repl [OPTIONS] [-- [ARGS]...]\n"
         svec!["--latest"],
         OutdatedFlags {
           filters: svec![],
-          kind: OutdatedKind::PrintOutdated { compatible: false },
+          kind: OutdatedKind::PrintOutdated {
+            compatible: false,
+            output_fmt: OutdatedOutputFmt::Table,
+          },
           recursive: false,
         },
       ),
diff --git a/cli/tools/registry/pm/deps.rs b/cli/tools/registry/pm/deps.rs
index d82e9954cd458a..20aff4151cc451 100644
--- a/cli/tools/registry/pm/deps.rs
+++ b/cli/tools/registry/pm/deps.rs
@@ -30,6 +30,7 @@ use deno_semver::VersionReq;
 use import_map::ImportMap;
 use import_map::ImportMapWithDiagnostics;
 use import_map::SpecifierMapEntry;
+use serde::Serialize;
 use tokio::sync::Semaphore;
 
 use crate::args::CliLockfile;
@@ -112,7 +113,7 @@ impl std::fmt::Debug for DepLocation {
   }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Serialize)]
 pub enum DepKind {
   Jsr,
   Npm,
diff --git a/cli/tools/registry/pm/outdated.rs b/cli/tools/registry/pm/outdated.rs
index 2a29014267d67e..2b054f53126219 100644
--- a/cli/tools/registry/pm/outdated.rs
+++ b/cli/tools/registry/pm/outdated.rs
@@ -4,15 +4,19 @@ use std::collections::HashSet;
 use std::sync::Arc;
 
 use deno_core::error::AnyError;
+use deno_core::serde_json;
 use deno_semver::package::PackageNv;
 use deno_semver::package::PackageReq;
 use deno_semver::VersionReq;
 use deno_terminal::colors;
+use serde::Serialize;
+use serde::Serializer;
 
 use crate::args::CacheSetting;
 use crate::args::CliOptions;
 use crate::args::Flags;
 use crate::args::OutdatedFlags;
+use crate::args::OutdatedOutputFmt;
 use crate::factory::CliFactory;
 use crate::file_fetcher::FileFetcher;
 use crate::jsr::JsrFetchResolver;
@@ -24,15 +28,29 @@ use super::deps::DepManager;
 use super::deps::DepManagerArgs;
 use super::deps::PackageLatestVersion;
 
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Serialize)]
 struct OutdatedPackage {
+  #[serde(rename = "specifier", serialize_with = "lowercase_serializer")]
   kind: DepKind,
+  #[serde(rename = "latest")]
   latest: String,
+  #[serde(rename = "update")]
   semver_compatible: String,
   current: String,
+  #[serde(rename = "package")]
   name: String,
 }
 
+fn lowercase_serializer<S>(kind: &DepKind, s: S) -> Result<S::Ok, S::Error>
+where
+  S: Serializer,
+{
+  match kind {
+    DepKind::Npm => s.serialize_str("npm"),
+    DepKind::Jsr => s.serialize_str("jsr"),
+  }
+}
+
 #[allow(clippy::print_stdout)]
 fn print_outdated_table(packages: &[OutdatedPackage]) {
   const HEADINGS: &[&str] = &["Package", "Current", "Update", "Latest"];
@@ -103,6 +121,7 @@ fn print_outdated_table(packages: &[OutdatedPackage]) {
 fn print_outdated(
   deps: &mut DepManager,
   compatible: bool,
+  output_fmt: OutdatedOutputFmt,
 ) -> Result<(), AnyError> {
   let mut outdated = Vec::new();
   let mut seen = std::collections::BTreeSet::new();
@@ -147,7 +166,13 @@ fn print_outdated(
 
   if !outdated.is_empty() {
     outdated.sort();
-    print_outdated_table(&outdated);
+    match output_fmt {
+      OutdatedOutputFmt::Table => print_outdated_table(&outdated),
+      OutdatedOutputFmt::Json => {
+        let json = serde_json::to_string_pretty(&outdated)?;
+        println!("{json}");
+      }
+    }
   }
 
   Ok(())
@@ -214,8 +239,11 @@ pub async fn outdated(
     crate::args::OutdatedKind::Update { latest } => {
       update(deps, latest, &filter_set, flags).await?;
     }
-    crate::args::OutdatedKind::PrintOutdated { compatible } => {
-      print_outdated(&mut deps, compatible)?;
+    crate::args::OutdatedKind::PrintOutdated {
+      compatible,
+      output_fmt,
+    } => {
+      print_outdated(&mut deps, compatible, output_fmt)?;
     }
   }