diff --git a/package.json b/package.json
index b9fa0de0..69078db3 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,7 @@
     "mocha": "^8.2.1",
     "proxyquire": "^2.1.0",
     "ts-node": "^9.0.0",
-    "typescript": "3.8.3"
+    "typescript": "4.2.3"
   },
   "engines": {
     "node": ">=8.0.0"
diff --git a/src/config.ts b/src/config.ts
index 6d6f957f..01e6f770 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -247,18 +247,18 @@ export class Config implements IConfig {
     s3.templates = {
       ...s3.templates,
       target: {
+        ...s3.templates && s3.templates.target,
         baseDir: '<%- bin %>',
         unversioned: "<%- channel === 'stable' ? '' : 'channels/' + channel + '/' %><%- bin %>-<%- platform %>-<%- arch %><%- ext %>",
         versioned: "<%- channel === 'stable' ? '' : 'channels/' + channel + '/' %><%- bin %>-v<%- version %>/<%- bin %>-v<%- version %>-<%- platform %>-<%- arch %><%- ext %>",
         manifest: "<%- channel === 'stable' ? '' : 'channels/' + channel + '/' %><%- platform %>-<%- arch %>",
-        ...s3.templates && s3.templates.target,
       },
       vanilla: {
+        ...s3.templates && s3.templates.vanilla,
         unversioned: "<%- channel === 'stable' ? '' : 'channels/' + channel + '/' %><%- bin %><%- ext %>",
         versioned: "<%- channel === 'stable' ? '' : 'channels/' + channel + '/' %><%- bin %>-v<%- version %>/<%- bin %>-v<%- version %><%- ext %>",
         baseDir: '<%- bin %>',
         manifest: "<%- channel === 'stable' ? '' : 'channels/' + channel + '/' %>version",
-        ...s3.templates && s3.templates.vanilla,
       },
     }
 
@@ -327,7 +327,7 @@ export class Config implements IConfig {
       return Promise.all((p.hooks[event] || [])
       .map(async hook => {
         try {
-          const f = tsPath(p.root, hook)
+          const f = tsPath(p.root, hook, this.pjson.oclif.tsConfig)
           debug('start', f)
           const search = (m: any): Hook<T> => {
             if (typeof m === 'function') return m
diff --git a/src/pjson.ts b/src/pjson.ts
index e0b8e6a0..23e387a3 100644
--- a/src/pjson.ts
+++ b/src/pjson.ts
@@ -1,8 +1,9 @@
 export interface PJSON {
   [k: string]: any;
-  dependencies?: {[name: string]: string};
+  dependencies?: { [name: string]: string };
   oclif: {
     schema?: number;
+    tsConfig?: string;
   };
 }
 
@@ -14,7 +15,7 @@ export namespace PJSON {
       schema?: number;
       title?: string;
       description?: string;
-      hooks?: { [name: string]: (string | string[]) };
+      hooks?: { [name: string]: string | string[] };
       commands?: string;
       plugins?: string[];
       devPlugins?: string[];
@@ -76,10 +77,14 @@ export namespace PJSON {
   export interface User extends PJSON {
     private?: boolean;
     oclif: PJSON['oclif'] & {
-      plugins?: (string | PluginTypes.User | PluginTypes.Link)[]; };
+      plugins?: (string | PluginTypes.User | PluginTypes.Link)[];
+    };
   }
 
-  export type PluginTypes = PluginTypes.User | PluginTypes.Link | {root: string}
+  export type PluginTypes =
+    | PluginTypes.User
+    | PluginTypes.Link
+    | { root: string };
   export namespace PluginTypes {
     export interface User {
       type: 'user';
diff --git a/src/plugin.ts b/src/plugin.ts
index 5dc82363..5d532177 100644
--- a/src/plugin.ts
+++ b/src/plugin.ts
@@ -211,7 +211,7 @@ export class Plugin implements IPlugin {
   }
 
   get commandsDir() {
-    return tsPath(this.root, this.pjson.oclif.commands)
+    return tsPath(this.root, this.pjson.oclif.commands, this.pjson.oclif.tsConfig)
   }
 
   get commandIDs() {
diff --git a/src/ts-node.ts b/src/ts-node.ts
index 34be09b5..231bd944 100644
--- a/src/ts-node.ts
+++ b/src/ts-node.ts
@@ -1,6 +1,7 @@
 import * as fs from 'fs'
 import * as path from 'path'
 import * as TSNode from 'ts-node'
+import type * as TS from 'typescript'
 
 import Debug from './debug'
 // eslint-disable-next-line new-cap
@@ -11,20 +12,11 @@ const rootDirs: string[] = []
 const typeRoots = [`${__dirname}/../node_modules/@types`]
 
 export interface TSConfig {
-  compilerOptions: {
-    rootDir?: string;
-    rootDirs?: string[];
-    outDir?: string;
-    target?: string;
-    esModuleInterop?: boolean;
-    experimentalDecorators?: boolean;
-    emitDecoratorMetadata?: boolean;
-  };
+  compilerOptions: TS.CompilerOptions;
 }
 
-function loadTSConfig(root: string): TSConfig | undefined {
-  const tsconfigPath = path.join(root, 'tsconfig.json')
-  let typescript: typeof import('typescript') | undefined
+function loadTSConfig(root: string, configPath = 'tsconfig.json'): TSConfig | undefined {
+  let typescript: typeof TS | undefined
   try {
     typescript = require('typescript')
   } catch {
@@ -32,25 +24,39 @@ function loadTSConfig(root: string): TSConfig | undefined {
       typescript = require(root + '/node_modules/typescript')
     } catch { }
   }
-
-  if (fs.existsSync(tsconfigPath) && typescript) {
-    const tsconfig = typescript.parseConfigFileTextToJson(
-      tsconfigPath,
-      fs.readFileSync(tsconfigPath, 'utf8'),
-    ).config
-    if (!tsconfig || !tsconfig.compilerOptions) {
-      throw new Error(
-        `Could not read and parse tsconfig.json at ${tsconfigPath}, or it ` +
+  if (typescript) {
+    const {findConfigFile, readConfigFile, parseJsonConfigFileContent, sys} = typescript
+    const tsconfigPath = findConfigFile(
+      root,
+      sys.fileExists,
+      configPath,
+    )
+    if (tsconfigPath) {
+      // Read the user's raw tsconfig file
+      const readFile = (path: string): string | undefined => fs.readFileSync(path).toString('utf8')
+      const tsconfig = readConfigFile(tsconfigPath, readFile).config
+      // Parse the raw config, resolving any configuration files it extends from
+      const compilerOptions = parseJsonConfigFileContent(
+        tsconfig,
+        sys,
+        root,
+      ).options
+      console.log({root, tsconfig, compilerOptions})
+      if (!tsconfig || !compilerOptions) {
+        throw new Error(
+          `Could not read and parse tsconfig.json at ${tsconfigPath}, or it ` +
         'did not contain a "compilerOptions" section.')
+      }
+      // Return only the combined compiler options
+      return {compilerOptions}
     }
-    return tsconfig
   }
 }
 
-function registerTSNode(root: string) {
+function registerTSNode(root: string, configPath?: string) {
   if (process.env.OCLIF_TS_NODE === '0') return
   if (tsconfigs[root]) return
-  const tsconfig = loadTSConfig(root)
+  const tsconfig = loadTSConfig(root, configPath)
   if (!tsconfig) return
   debug('registering ts-node at', root)
   const tsNodePath = require.resolve('ts-node', {paths: [root, __dirname]})
@@ -71,6 +77,7 @@ function registerTSNode(root: string) {
       // cache: false,
       // typeCheck: true,
       compilerOptions: {
+        ...tsconfig.compilerOptions,
         esModuleInterop: tsconfig.compilerOptions.esModuleInterop,
         target: tsconfig.compilerOptions.target || 'es2017',
         experimentalDecorators: tsconfig.compilerOptions.experimentalDecorators || false,
@@ -92,13 +99,13 @@ function registerTSNode(root: string) {
  * this is for developing typescript plugins/CLIs
  * if there is a tsconfig and the original sources exist, it attempts to require ts-
  */
-export function tsPath(root: string, orig: string): string
-export function tsPath(root: string, orig: string | undefined): string | undefined
-export function tsPath(root: string, orig: string | undefined): string | undefined {
+export function tsPath(root: string, orig: string, configPath?: string): string
+export function tsPath(root: string, orig: string | undefined, configPath?: string): string | undefined
+export function tsPath(root: string, orig: string | undefined, configPath?: string): string | undefined {
   if (!orig) return orig
   orig = path.join(root, orig)
   try {
-    registerTSNode(root)
+    registerTSNode(root, configPath)
     const tsconfig = tsconfigs[root]
     if (!tsconfig) return orig
     const {rootDir, rootDirs, outDir} = tsconfig.compilerOptions
diff --git a/test/fixtures/typescript/tsconfig.custom.json b/test/fixtures/typescript/tsconfig.custom.json
new file mode 100644
index 00000000..3c9ab9ac
--- /dev/null
+++ b/test/fixtures/typescript/tsconfig.custom.json
@@ -0,0 +1,4 @@
+{
+    "extends": "./tsconfig.json"
+}
+  
\ No newline at end of file
diff --git a/test/test.ts b/test/test.ts
index 175eb103..c1b88343 100644
--- a/test/test.ts
+++ b/test/test.ts
@@ -5,6 +5,7 @@ import * as Config from '../src'
 export const fancy = base
 .register('resetConfig', () => ({
   run(ctx: {config: Config.IConfig}) {
+    // @ts-expect-error
     delete ctx.config
   },
 }))
diff --git a/test/ts-node.test.ts b/test/ts-node.test.ts
index 590f3e10..f9d89d64 100644
--- a/test/ts-node.test.ts
+++ b/test/ts-node.test.ts
@@ -2,7 +2,7 @@ import * as path from 'path'
 import * as proxyquire from 'proxyquire'
 import * as tsNode from 'ts-node'
 
-import {TSConfig} from '../src/ts-node'
+import {TSConfig, tsPath} from '../src/ts-node'
 
 import {expect, fancy} from './test'
 
@@ -40,6 +40,11 @@ describe('tsPath', () => {
     expect(result).to.equal(path.join(root, orig))
   })
 
+  it('should resolve a .ts file using custom config using "extends"', () => {
+    const result = tsPath(root, orig, 'tsconfig.custom.json')
+    expect(result).to.equal(path.join(root, orig))
+  })
+
   withMockTsConfig()
   .it('should leave esModuleInterop undefined by default', ctx => {
     ctx.tsNodePlugin.tsPath(root, orig)
diff --git a/yarn.lock b/yarn.lock
index e110bdad..dd5d4246 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1706,12 +1706,11 @@ lodash.zip@^4.2.0:
   resolved "https://registry.yarnpkg.com/lodash.zip/-/lodash.zip-4.2.0.tgz#ec6662e4896408ed4ab6c542a3990b72cc080020"
   integrity sha1-7GZi5IlkCO1KtsVCo5kLcswIACA=
 
-lodash@^4.17.11, lodash@^4.17.15, lodash@^4.17.19, lodash@^4.17.20:
+lodash@^4.17.11, lodash@^4.17.15, lodash@^4.17.20:
   version "4.17.21"
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
   integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
 
-
 log-symbols@4.0.0:
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-4.0.0.tgz#69b3cc46d20f448eccdb75ea1fa733d9e821c920"
@@ -2776,10 +2775,10 @@ type-fest@^0.8.1:
   resolved "https://registry.yarnpkg.com/type-fest/-/type-fest-0.8.1.tgz#09e249ebde851d3b1e48d27c105444667f17b83d"
   integrity sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==
 
-typescript@3.8.3:
-  version "3.8.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-3.8.3.tgz#409eb8544ea0335711205869ec458ab109ee1061"
-  integrity sha512-MYlEfn5VrLNsgudQTVJeNaQFUAI7DkhnOjdpAp4T+ku1TfQClewlbSuTVHiA+8skNBgaf02TL/kLOvig4y3G8w==
+typescript@4.2.3:
+  version "4.2.3"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.2.3.tgz#39062d8019912d43726298f09493d598048c1ce3"
+  integrity sha512-qOcYwxaByStAWrBf4x0fibwZvMRG+r4cQoTjbPtUlrWjBHbmCAww1i448U0GJ+3cNNEtebDteo/cHOR3xJ4wEw==
 
 uglify-js@^3.1.4:
   version "3.7.3"