diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index fe364f32b68716059c8db13d82b4a165afbb1ef8..6f0d299ebe8e5a9323ab308315fa9b6a8b819230 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -14,6 +14,7 @@ For a detailed view of what's changed, refer to the {url-repo}/commits[commit hi
 
 * rename `on_failure` key on run config to `failure`; keep `on_failure` key as alias (#38)
 * map the `env.PWD` context variable to the resolved value of the `dir` key on the run entry (#31)
+* cache the result of previous where calls on Windows to avoid redundant lookups (#40)
 
 === Fixed
 
diff --git a/packages/collector-extension/lib/index.js b/packages/collector-extension/lib/index.js
index 0140f5f0f75b1c83230f2c9acac13f15f04b8c73..4905b9005d74f9e32f627763249f1731c00e5efa 100644
--- a/packages/collector-extension/lib/index.js
+++ b/packages/collector-extension/lib/index.js
@@ -29,6 +29,7 @@ module.exports.register = function ({ config: { createWorktrees = 'auto', keepWo
     const cacheDir = ospath.join(getBaseCacheDir(playbook), 'collector')
     await fsp.mkdir(cacheDir, { recursive: true })
     const gitCache = {}
+    const runCache = { where: {} }
     const managedWorktrees = new Map()
     for (const componentVersionBucket of contentAggregate.slice()) {
       const { origins = [] } = componentVersionBucket
@@ -126,7 +127,7 @@ module.exports.register = function ({ config: { createWorktrees = 'auto', keepWo
           for (const clean of cleans) await fsp.rm(clean.dir, { recursive: true, force: true })
           for (const { dir: cwd, command, local, shell, env, failure } of runs) {
             try {
-              await runCommand(command, { cwd, local, shell: !!shell, env, quiet })
+              await runCommand(command, { cwd, local, shell: !!shell, env, quiet, cache: runCache })
             } catch (err) {
               const loc = worktree || url
               const qualifier = worktree ? ' <worktree>' : remote && worktree === false ? ` <remotes/${remote}>` : ''
diff --git a/packages/collector-extension/lib/util/run-command.js b/packages/collector-extension/lib/util/run-command.js
index ef08927cc872a59958646e94bc734fd7a8906c24..6cee10b290fea9905e29aeb25edcbda9ba838f22 100644
--- a/packages/collector-extension/lib/util/run-command.js
+++ b/packages/collector-extension/lib/util/run-command.js
@@ -16,7 +16,7 @@ async function runCommand (cmd = '', opts = {}) {
   let cmdv = parseCommand(String(cmd), { preserveQuotes: shell })
   if (!cmdv.length) throw new TypeError('Command not specified')
   let cmd0 = cmdv[0]
-  const { quiet, local, ...spawnOpts } = opts
+  const { quiet, local, cache: { where = {} } = {}, ...spawnOpts } = opts
   if (IS_WIN) {
     if (~cmd0.indexOf('/')) cmdv[0] = cmd0 = cmd0.replace(/[/]/g, ospath.sep)
     if (shell) {
@@ -27,7 +27,7 @@ async function runCommand (cmd = '', opts = {}) {
         if (bare && local) cmdv[0] = '.' + ospath.sep + cmd0
       } else {
         if (bare && !local) {
-          cmdv[0] = await new Promise((resolve) => {
+          cmdv[0] = where[cmd0] ??= await new Promise((resolve) => {
             execFile('where', [cmd0 + '.???'], { cwd: opts.cwd, windowsHide: true }, (_, results) => {
               if (!(results = results.trimEnd())) return resolve(cmd0)
               const exts = results.split('\r\n', 2).reduce((accum, it) => {
diff --git a/packages/collector-extension/test/collector-extension-test.js b/packages/collector-extension/test/collector-extension-test.js
index 66b6238a17909b046945c6a684b45979848f90b7..125286e3698472829e1da4ceb91bab5464567e1a 100644
--- a/packages/collector-extension/test/collector-extension-test.js
+++ b/packages/collector-extension/test/collector-extension-test.js
@@ -862,7 +862,7 @@ describe('collector extension', () => {
 
       it('should run batch script on PATH in Windows', async () => {
         const collectorConfig = {
-          run: { command: 'npm run gen-antora-yml' },
+          run: [{ command: 'npm run' }, { command: 'npm run gen-antora-yml' }],
           scan: { dir: 'target/docs' },
         }
         await runScenario({