diff --git a/docs/user/config/index.md b/docs/user/config/index.md
index c7ee515358..5e06e4fba9 100644
--- a/docs/user/config/index.md
+++ b/docs/user/config/index.md
@@ -188,10 +188,10 @@ All options have default values which should fit most of the projects. Click on
 | Option | Description | Type | Default |
 |---|---|---|---|
 | [**`compiler`**][compiler] | [TypeScript module to use as compiler.][compiler] | `string` | `"typescript"` |
-| [**`tsConfig`**][tsConfig] | [TypeScript compiler related configuration.][tsConfig] | `string`\|`object`\|`boolean` | _auto_ |
-| [**`isolatedModules`**][isolatedModules] | [Disable type-checking][isolatedModules] | `boolean` | `false` |
-| [**`diagnostics`**][diagnostics] | [Diagnostics related configuration.][diagnostics] | `boolean`\|`object` | `true` |
-| [**`babelConfig`**][babelConfig] | [Babel(Jest) related configuration.][babelConfig] | `boolean`\|`object` | _disabled_ |
+| [**`tsConfig` or `tsconfig`**][tsConfig] | [TypeScript compiler related configuration.][tsConfig] | `string`\|`object`\|`boolean` | _auto_ |
+| [**`isolatedModules`**][isolatedModules] | [Disable type-checking][isolatedModules] | `boolean` | _disabled_ |
+| [**`diagnostics`**][diagnostics] | [Diagnostics related configuration.][diagnostics] | `boolean`\|`object` | _enabled_ |
+| [**`babelConfig`**][babelConfig] | [Babel(Jest) related configuration.][babelConfig] | `boolean`\|`string`\|`object` | _disabled_ |
 | [**`stringifyContentPathRegex`**][stringifyContentPathRegex] | [Files which will become modules returning self content.][stringifyContentPathRegex] | `string`\|`RegExp` | _disabled_ |
 | [**`packageJson`**][packageJson] | [Package metadata.][packageJson] | `string`\|`object`\|`boolean` | _auto_ |
 
diff --git a/docs/user/config/tsConfig.md b/docs/user/config/tsConfig.md
index 9c0a93d034..218ebc4cf5 100644
--- a/docs/user/config/tsConfig.md
+++ b/docs/user/config/tsConfig.md
@@ -2,9 +2,9 @@
 title: TypeScript Config option
 ---
 
-The `tsConfig` option allows you to define the which `tsconfig` JSON file to use. An inline compiler options object can also be specified instead of the path to a file.
+The `tsConfig` option (alias `tsconfig`) allows you to define which `tsconfig` JSON file to use. An inline [compiler options][] object can also be specified instead of a file path.
 
-By default, it'll use the default TypeScript and use the project's `tsconfig.json` file. If it cannot find one, it'll use defaults TypeScript compiler options (except `es5` is used as target instead of `es3`).
+By default `ts-jest` will try to find a `tsconfig.json` in your project. If it cannot find one, it will use the default TypeScript [compiler options][]; except, `ES5` is used as `target` instead of `ES3`.
 
 If you need to use defaults and force `ts-jest` to use the defaults even if there is a `tsconfig.json` in your project, you can set this option to `false`.
 
@@ -48,7 +48,7 @@ module.exports = {
 
 #### Inline compiler options
 
-Refer to the [TypeScript compiler options](https://www.typescriptlang.org/docs/handbook/compiler-options.html) to know what can be used.
+Refer to the TypeScript [compiler options][] for reference.
 It's basically the same object you'd put in your `tsconfig.json`'s `compilerOptions`.
 
 <div class="row"><div class="col-md-6" markdown="block">
@@ -89,7 +89,7 @@ module.exports = {
 
 #### Disable auto-lookup
 
-By default `ts-jest` will try to find the `tsconfig.json` in your project. But you may want to not use it at all and keep TypeScript default options. You can achieve this by setting `tsConfig` to `false`.
+By default `ts-jest` will try to find a `tsconfig.json` in your project. But you may not want to use it at all and keep TypeScript default options. You can achieve this by setting `tsConfig` to `false`.
 
 <div class="row"><div class="col-md-6" markdown="block">
 
@@ -122,3 +122,5 @@ module.exports = {
 ```
 
 </div></div>
+
+[compiler options]: https://www.typescriptlang.org/docs/handbook/compiler-options.html#compiler-options
diff --git a/src/config/config-set.spec.ts b/src/config/config-set.spec.ts
index 887627d33f..6f4a250141 100644
--- a/src/config/config-set.spec.ts
+++ b/src/config/config-set.spec.ts
@@ -478,8 +478,8 @@ describe('typescript', () => {
     expect(get().fileNames).toContain(normalizeSlashes(__filename))
   })
 
-  it('should include compiler config from `tsConfig` option key', () => {
-    expect(get({ tsConfig: { baseUrl: 'src/config' } }).options.baseUrl).toBe(normalizeSlashes(__dirname))
+  it.each(['tsConfig', 'tsconfig'])('should include compiler config from `%s` option key', (key: string) => {
+    expect(get({ [key]: { baseUrl: 'src/config' } }).options.baseUrl).toBe(normalizeSlashes(__dirname))
   })
 
   it('should include compiler config from base config', () => {
diff --git a/src/config/config-set.ts b/src/config/config-set.ts
index 1892cf9413..f0c7e8eca8 100644
--- a/src/config/config-set.ts
+++ b/src/config/config-set.ts
@@ -222,9 +222,9 @@ export class ConfigSet {
     const options: TsJestGlobalOptions = { ...globals['ts-jest'] }
 
     // tsconfig
-    const { tsConfig: tsConfigOpt } = options
+    const tsConfigOpt = options.tsConfig ?? options.tsconfig ?? true
     let tsConfig: TsJestConfig['tsConfig']
-    if (typeof tsConfigOpt === 'string' || tsConfigOpt == null || tsConfigOpt === true) {
+    if (typeof tsConfigOpt === 'string' || tsConfigOpt === true) {
       tsConfig = {
         kind: 'file',
         value: typeof tsConfigOpt === 'string' ? this.resolvePath(tsConfigOpt) : undefined,
diff --git a/src/types.ts b/src/types.ts
index 1b03b5e870..6061dba0d6 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -30,28 +30,44 @@ export type BabelConfig = _babel.TransformOptions
 export interface TsJestGlobalOptions {
   /**
    * Compiler options. It can be:
-   *     - `true` (or `undefined`, it's the default): use default tsconfig file
-   *     - `false`: do NOT use default config file
-   *     - `path/to/tsconfig.json`: path to a specific tsconfig file (<rootDir> can be used)
-   *     - `{...}`: an object with inline compiler options
+   * - `true` (or `undefined`, it's the default): use default tsconfig file
+   * - `false`: do NOT use default config file
+   * - `path/to/tsconfig.json`: path to a specific tsconfig file (<rootDir> can be used)
+   * - `{...}`: an object with inline compiler options
+   * @default undefined uses the default tsconfig file
+   * @alias tsconfig
    */
   tsConfig?: boolean | string | _ts.CompilerOptions
 
+  /**
+   * Compiler options. It can be:
+   * - `true` (or `undefined`, it's the default): use default tsconfig file
+   * - `false`: do NOT use default config file
+   * - `path/to/tsconfig.json`: path to a specific tsconfig file (<rootDir> can be used)
+   * - `{...}`: an object with inline compiler options
+   * @default undefined uses the default tsconfig file
+   * @alias tsConfig
+   */
+  tsconfig?: boolean | string | _ts.CompilerOptions
+
   /**
    * packageJson. It can be:
-   *     - `true` (or `undefined`, it's the default): use default package.json file
-   *     - `path/to/package.json`: path to a specific package.json file (<rootDir> can be used)
-   *     - `{...}`: contents of a package.json
+   * - `true` (or `undefined`, it's the default): use default package.json file
+   * - `path/to/package.json`: path to a specific package.json file (<rootDir> can be used)
+   * - `{...}`: contents of a package.json
+   * @default undefined uses the default package.json file
    */
   packageJson?: boolean | string | object
 
   /**
-   * Whether to compile files as isolated modules (disables some features and type-checking, default to `false`):
+   * Compiles files as isolated modules (disables some features and type-checking)
+   * @default undefined (disabled)
    */
   isolatedModules?: boolean
 
   /**
-   * Compiler to use (default to 'typescript'):
+   * Compiler to use
+   * @default 'typescript'
    */
   compiler?: string
 
@@ -62,33 +78,45 @@ export interface TsJestGlobalOptions {
 
   /**
    * TS diagnostics - less to be reported if `isolatedModules` is `true`. It can be:
-   *     - `true` (or `undefined`, it's the default): show all diagnostics
-   *     - `false`: hide diagnostics of all files (kind of useless)
-   *     - `{...}`: an inline object with fine grained settings
+   * - `true` (or `undefined`, it's the default): show all diagnostics
+   * - `false`: hide diagnostics of all files (kind of useless)
+   * - `{...}`: an inline object with fine grained settings
+   * @default undefined shows all diagnostics
    */
   diagnostics?:
     | boolean
     | {
+        /**
+         * Enables colorful and pretty output of errors
+         * @default undefined (enabled)
+         */
         pretty?: boolean
         /**
-         * Ignore TypeScript warnings by diagnostic code.
+         * List of TypeScript diagnostic error codes to ignore
+         * [here](https://github.com/Microsoft/TypeScript/blob/master/src/compiler/diagnosticMessages.json).
+         * @see https://github.com/Microsoft/TypeScript/blob/master/src/compiler/diagnosticMessages.json
+         * @default [6059,18002,18003]
          */
         ignoreCodes?: number | string | (number | string)[]
+        /**
+         * If specified, diagnostics of source files which path does **not** match
+         * will be ignored
+         */
         pathRegex?: RegExp | string
         /**
-         * Logs TypeScript errors to stderr instead of throwing exceptions.
-         *
-         * @default false
+         * Logs TypeScript errors to stderr instead of throwing exceptions
+         * @default undefined (disabled)
          */
         warnOnly?: boolean
       }
 
   /**
    * Babel config. It can be:
-   *    - `false` (or `undefined`, it's the default): do NOT use babel
-   *    - `true`: use babel using default babelrc file
-   *    - `path/to/.babelrc`: path to a babelrc file (<rootDir> can be used)
-   *     - `{...}`: an object with inline babel options
+   * - `false` (or `undefined`, it's the default): do NOT use babel
+   * - `true`: use babel using default babelrc file
+   * - `path/to/.babelrc`: path to a babelrc file (<rootDir> can be used)
+   * - `{...}`: an object with inline babel options
+   * @default undefined does NOT use babel
    */
   babelConfig?: boolean | string | BabelConfig