diff --git a/src/help-linux.in b/src/help-linux.in
index 8ced196f..b7bfa0c2 100644
--- a/src/help-linux.in
+++ b/src/help-linux.in
@@ -108,6 +108,9 @@ const HELP_ADD: &str = "
   - `rig add x.y` adds the latest release within the `x.y` minor branch.
   - `rig add oldrel/n` adds the latest release within the `n`th previous
     minor branch (`oldrel` is the same as `oldrel/1`).
+  - `rig add renv.lock` or `rig add <dir>` installs the R version specified
+    in the renv.lock file. If a directory is given, rig looks for an
+    renv.lock file in that directory.
 
   You need to run this command with `sudo`: `sudo rig add ...`,
   otherwise rig will need to ask for your password.
@@ -130,7 +133,13 @@ const HELP_ADD_EXAMPLES: &str = "\x1b[4m\x1b[1mExamples:\x1b[22m\x1b[24m
   rig add 4.1.2
 
   # Install latest version within a minor branch
-  rig add 4.1";
+  rig add 4.1
+
+  # Install the R version specified in renv.lock
+  rig add renv.lock
+
+  # Install R version from a project's renv.lock
+  rig add path/to/project";
 
 const HELP_RM: &str = "
 \x1b[4m\x1b[1mDescription:\x1b[22m\x1b[24m
diff --git a/src/help-macos.in b/src/help-macos.in
index 65822bb3..d63b2921 100644
--- a/src/help-macos.in
+++ b/src/help-macos.in
@@ -115,6 +115,9 @@ const HELP_ADD: &str = "
   - `rig add oldrel/n` adds the latest release within the `n`th previous
     minor branch (`oldrel` is the same as `oldrel/1`).
   - `rig add <url>` uses a `.pkg` installer from `<url>`.
+  - `rig add renv.lock` or `rig add <dir>` installs the R version specified
+    in the renv.lock file. If a directory is given, rig looks for an
+    renv.lock file in that directory.
 
   Usually you need to run this command with `sudo`: `sudo rig add ...`,
   otherwise rig will need to ask for your password.
@@ -150,7 +153,13 @@ const HELP_ADD_EXAMPLES: &str = "\x1b[4m\x1b[1mExamples:\x1b[22m\x1b[24m
   rig add -a arm64 release
 
   # Install x86_64 build of R (default on x86_64 macs)
-  rig add -a x86_64 release";
+  rig add -a x86_64 release
+
+  # Install the R version specified in renv.lock
+  rig add renv.lock
+
+  # Install R version from a project's renv.lock
+  rig add path/to/project";
 
 const HELP_RM: &str = "
 \x1b[4m\x1b[1mDescription:\x1b[22m\x1b[24m
diff --git a/src/help-windows.in b/src/help-windows.in
index 6cf0cf9e..af0a1d57 100644
--- a/src/help-windows.in
+++ b/src/help-windows.in
@@ -110,6 +110,9 @@ const HELP_ADD: &str = "
   - `rig add oldrel/n` adds the latest release within the `n`th previous
     minor branch (`oldrel` is the same as `oldrel/1`).
   - `rig add <url>` uses a `.pkg` installer from `<url>`.
+  - `rig add renv.lock` or `rig add <dir>` installs the R version specified
+    in the renv.lock file. If a directory is given, rig looks for an
+    renv.lock file in that directory.
 
   `rig add` will call the following rig command after the installation,
   to set up the newly installed version:
@@ -149,7 +152,13 @@ const HELP_ADD_EXAMPLES: &str = "\x1b[4m\x1b[1mExamples:\x1b[22m\x1b[24m
   rig add 4.1
 
   # Install all needed Rtools versions
-  rig add rtools";
+  rig add rtools
+
+  # Install the R version specified in renv.lock
+  rig add renv.lock
+
+  # Install R version from a project's renv.lock
+  rig add path/to/project";
 
 const HELP_RM: &str = "
 \x1b[4m\x1b[1mDescription:\x1b[22m\x1b[24m
diff --git a/src/resolve.rs b/src/resolve.rs
index 8b1faac4..304970c8 100644
--- a/src/resolve.rs
+++ b/src/resolve.rs
@@ -11,11 +11,14 @@ use simple_error::bail;
 #[cfg(target_os = "windows")]
 use std::sync::{LazyLock, RwLock};
 
+use std::path::Path;
+
 use crate::common::*;
 use crate::download::*;
 #[cfg(target_os = "windows")]
 use crate::hardcoded::*;
 use crate::output::OUTPUT;
+use crate::renv;
 use crate::rversion::*;
 use crate::utils::*;
 
@@ -23,10 +26,41 @@ const API_URI: &str = "https://api.r-hub.io/rversions/resolve/";
 #[cfg(target_os = "windows")]
 const API_ROOT: &str = "https://api.r-hub.io/rversions/";
 
+pub fn resolve_lockfile_version(str: &str) -> Result<Option<String>, Box<dyn Error>> {
+    let path = Path::new(str);
+
+    // Direct path to renv.lock
+    if path.file_name() == Some(std::ffi::OsStr::new("renv.lock")) && path.exists() {
+        let ver = renv::parse_r_version(path.to_path_buf())?;
+        OUTPUT.info(&format!("Installing R {} from renv.lock", ver));
+        return Ok(Some(ver));
+    }
+
+    // Directory containing renv.lock
+    if path.is_dir() {
+        let lockfile = path.join("renv.lock");
+        if lockfile.exists() {
+            let ver = renv::parse_r_version(lockfile)?;
+            OUTPUT.info(&format!("Installing R {} from renv.lock", ver));
+            return Ok(Some(ver));
+        }
+    }
+
+    Ok(None)
+}
+
 pub fn get_resolve(args: &ArgMatches) -> Result<Rversion, Box<dyn Error>> {
     let platform = get_platform(args)?;
     let arch = get_arch(&platform, args);
     let str: &String = args.get_one("str").unwrap();
+
+    // Check if str is a path to renv.lock or a directory containing one
+    let resolved_ver = resolve_lockfile_version(str)?;
+    let str = match &resolved_ver {
+        Some(ver) => ver.as_str(),
+        None => str.as_str(),
+    };
+
     let eps = vec![str.to_string()];
 
     if str.len() > 8 && (&str[..7] == "http://" || &str[..8] == "https://") {
@@ -186,3 +220,57 @@ pub fn get_rtools_version(version: &str, arch: &str) -> Result<RtoolsVersion, Bo
     error!("{}", msg);
     bail!(msg)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::env;
+
+    #[test]
+    fn test_resolve_lockfile_direct_path() {
+        let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+        let lockfile = format!("{}/tests/fixtures/renv-project/renv.lock", manifest_dir);
+        let result = resolve_lockfile_version(&lockfile).unwrap();
+        assert_eq!(result, Some("4.4.1".to_string()));
+    }
+
+    #[test]
+    fn test_resolve_lockfile_directory() {
+        let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+        let dir = format!("{}/tests/fixtures/renv-project", manifest_dir);
+        let result = resolve_lockfile_version(&dir).unwrap();
+        assert_eq!(result, Some("4.4.1".to_string()));
+    }
+
+    #[test]
+    fn test_resolve_lockfile_not_a_path() {
+        let result = resolve_lockfile_version("release").unwrap();
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn test_resolve_lockfile_version_string() {
+        let result = resolve_lockfile_version("4.4.1").unwrap();
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn test_resolve_lockfile_devel() {
+        let result = resolve_lockfile_version("devel").unwrap();
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn test_resolve_lockfile_nonexistent_path() {
+        let result = resolve_lockfile_version("/nonexistent/renv.lock").unwrap();
+        assert_eq!(result, None);
+    }
+
+    #[test]
+    fn test_resolve_lockfile_dir_without_lockfile() {
+        let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+        let dir = format!("{}/tests/fixtures/app-shiny", manifest_dir);
+        let result = resolve_lockfile_version(&dir).unwrap();
+        assert_eq!(result, None);
+    }
+}
diff --git a/tests/fixtures/renv-project/renv.lock b/tests/fixtures/renv-project/renv.lock
new file mode 100644
index 00000000..05dbcba5
--- /dev/null
+++ b/tests/fixtures/renv-project/renv.lock
@@ -0,0 +1,19 @@
+{
+  "R": {
+    "Version": "4.4.1",
+    "Repositories": [
+      {
+        "Name": "CRAN",
+        "URL": "https://cloud.r-project.org"
+      }
+    ]
+  },
+  "Packages": {
+    "renv": {
+      "Package": "renv",
+      "Version": "1.1.5",
+      "Source": "Repository",
+      "Repository": "CRAN"
+    }
+  }
+}