diff --git a/Cargo.lock b/Cargo.lock
index 21fea637f0a..9c1b591349b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3875,7 +3875,9 @@ dependencies = [
  "eth2_wallet",
  "ethereum_hashing",
  "ethereum_ssz",
+ "execution_layer",
  "genesis",
+ "hex",
  "int_to_bytes",
  "lighthouse_network",
  "lighthouse_version",
diff --git a/lcli/Cargo.toml b/lcli/Cargo.toml
index 854f718c591..d6c3ff197ae 100644
--- a/lcli/Cargo.toml
+++ b/lcli/Cargo.toml
@@ -43,6 +43,8 @@ beacon_chain = { workspace = true }
 store = { workspace = true }
 malloc_utils = { workspace = true }
 rayon = { workspace = true }
+execution_layer = { workspace = true }
+hex = { workspace = true }
 
 [package.metadata.cargo-udeps.ignore]
 normal = ["malloc_utils"]
diff --git a/lcli/src/main.rs b/lcli/src/main.rs
index 2aa855474fa..17fafe6ec1e 100644
--- a/lcli/src/main.rs
+++ b/lcli/src/main.rs
@@ -11,6 +11,7 @@ mod indexed_attestations;
 mod insecure_validators;
 mod interop_genesis;
 mod mnemonic_validators;
+mod mock_el;
 mod new_testnet;
 mod parse_ssz;
 mod replace_state_pubkeys;
@@ -891,6 +892,61 @@ fn main() {
                         .help("Number of repeat runs, useful for benchmarking."),
                 )
         )
+        .subcommand(
+            SubCommand::with_name("mock-el")
+                .about("Creates a mock execution layer server. This is NOT SAFE and should only \
+                be used for testing and development on testnets. Do not use in production. Do not \
+                use on mainnet. It cannot perform validator duties.")
+                .arg(
+                    Arg::with_name("jwt-output-path")
+                        .long("jwt-output-path")
+                        .value_name("PATH")
+                        .takes_value(true)
+                        .required(true)
+                        .help("Path to write the JWT secret."),
+                )
+                .arg(
+                    Arg::with_name("listen-address")
+                        .long("listen-address")
+                        .value_name("IP_ADDRESS")
+                        .takes_value(true)
+                        .help("The server will listen on this address.")
+                        .default_value("127.0.0.1")
+                )
+                .arg(
+                    Arg::with_name("listen-port")
+                        .long("listen-port")
+                        .value_name("PORT")
+                        .takes_value(true)
+                        .help("The server will listen on this port.")
+                        .default_value("8551")
+                )
+                .arg(
+                    Arg::with_name("all-payloads-valid")
+                        .long("all-payloads-valid")
+                        .takes_value(true)
+                        .help("Controls the response to newPayload and forkchoiceUpdated. \
+                            Set to 'true' to return VALID. Set to 'false' to return SYNCING.")
+                        .default_value("false")
+                        .hidden(true)
+                )
+                .arg(
+                    Arg::with_name("shanghai-time")
+                        .long("shanghai-time")
+                        .value_name("UNIX_TIMESTAMP")
+                        .takes_value(true)
+                        .help("The payload timestamp that enables Shanghai. Defaults to the mainnet value.")
+                        .default_value("1681338479")
+                )
+                .arg(
+                    Arg::with_name("cancun-time")
+                        .long("cancun-time")
+                        .value_name("UNIX_TIMESTAMP")
+                        .takes_value(true)
+                        .help("The payload timestamp that enables Cancun. No default is provided \
+                                until Cancun is triggered on mainnet.")
+                )
+        )
         .get_matches();
 
     let result = matches
@@ -1032,6 +1088,8 @@ fn run<T: EthSpec>(
             state_root::run::<T>(env, network_config, matches)
                 .map_err(|e| format!("Failed to run state-root command: {}", e))
         }
+        ("mock-el", Some(matches)) => mock_el::run::<T>(env, matches)
+            .map_err(|e| format!("Failed to run mock-el command: {}", e)),
         (other, _) => Err(format!("Unknown subcommand {}. See --help.", other)),
     }
 }
diff --git a/lcli/src/mock_el.rs b/lcli/src/mock_el.rs
new file mode 100644
index 00000000000..094e23c3b40
--- /dev/null
+++ b/lcli/src/mock_el.rs
@@ -0,0 +1,62 @@
+use clap::ArgMatches;
+use clap_utils::{parse_optional, parse_required};
+use environment::Environment;
+use execution_layer::{
+    auth::JwtKey,
+    test_utils::{
+        Config, MockExecutionConfig, MockServer, DEFAULT_JWT_SECRET, DEFAULT_TERMINAL_BLOCK,
+    },
+};
+use std::net::Ipv4Addr;
+use std::path::PathBuf;
+use types::*;
+
+pub fn run<T: EthSpec>(mut env: Environment<T>, matches: &ArgMatches) -> Result<(), String> {
+    let jwt_path: PathBuf = parse_required(matches, "jwt-output-path")?;
+    let listen_addr: Ipv4Addr = parse_required(matches, "listen-address")?;
+    let listen_port: u16 = parse_required(matches, "listen-port")?;
+    let all_payloads_valid: bool = parse_required(matches, "all-payloads-valid")?;
+    let shanghai_time = parse_required(matches, "shanghai-time")?;
+    let cancun_time = parse_optional(matches, "cancun-time")?;
+
+    let handle = env.core_context().executor.handle().unwrap();
+    let spec = &T::default_spec();
+    let jwt_key = JwtKey::from_slice(&DEFAULT_JWT_SECRET).unwrap();
+    std::fs::write(jwt_path, hex::encode(DEFAULT_JWT_SECRET)).unwrap();
+
+    let config = MockExecutionConfig {
+        server_config: Config {
+            listen_addr,
+            listen_port,
+        },
+        jwt_key,
+        terminal_difficulty: spec.terminal_total_difficulty,
+        terminal_block: DEFAULT_TERMINAL_BLOCK,
+        terminal_block_hash: spec.terminal_block_hash,
+        shanghai_time: Some(shanghai_time),
+        cancun_time,
+    };
+    let kzg = None;
+    let server: MockServer<T> = MockServer::new_with_config(&handle, config, kzg);
+
+    if all_payloads_valid {
+        eprintln!(
+            "Using --all-payloads-valid=true can be dangerous. \
+            Never use this flag when operating validators."
+        );
+        // Indicate that all payloads are valid.
+        server.all_payloads_valid();
+    }
+
+    eprintln!(
+        "This tool is for TESTING PURPOSES ONLY. Do not use in production or on mainnet. \
+        It cannot perform validator duties. It may cause nodes to follow an invalid chain."
+    );
+    eprintln!("Server listening on {}:{}", listen_addr, listen_port);
+
+    let shutdown_reason = env.block_until_shutdown_requested()?;
+
+    eprintln!("Shutting down: {:?}", shutdown_reason);
+
+    Ok(())
+}