diff --git a/.eslintrc b/.eslintrc
index 238612fbd..10b89fb05 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -9,6 +9,7 @@
   "extends": ["eslint-config-postcss", "prettier"],
   "plugins": ["prettier"],
   "rules": {
+    "no-unused-vars": [2, {"args": "all", "argsIgnorePattern": "^_"}],
     "prettier/prettier": [
       "error",
       {
diff --git a/__tests__/processPlugins.test.js b/__tests__/processPlugins.test.js
index 58e8b85e0..f70c12e6f 100644
--- a/__tests__/processPlugins.test.js
+++ b/__tests__/processPlugins.test.js
@@ -47,7 +47,7 @@ test('plugins can create utilities with object syntax', () => {
         object-fit: cover
       }
     }
-    `)
+  `)
 })
 
 test('plugins can create utilities with arrays of objects', () => {
@@ -1206,3 +1206,84 @@ test('prefix will prefix all classes in a selector', () => {
     }
     `)
 })
+
+test('plugins can be provided as an object with a handler function', () => {
+  const { components, utilities } = processPlugins(
+    [
+      {
+        handler({ addUtilities }) {
+          addUtilities({
+            '.object-fill': {
+              'object-fit': 'fill',
+            },
+            '.object-contain': {
+              'object-fit': 'contain',
+            },
+            '.object-cover': {
+              'object-fit': 'cover',
+            },
+          })
+        },
+      },
+    ],
+    makeConfig()
+  )
+
+  expect(components.length).toBe(0)
+  expect(css(utilities)).toMatchCss(`
+    @variants {
+      .object-fill {
+        object-fit: fill
+      }
+      .object-contain {
+        object-fit: contain
+      }
+      .object-cover {
+        object-fit: cover
+      }
+    }
+  `)
+})
+
+test('plugins can provide a config but no handler', () => {
+  const { components, utilities } = processPlugins(
+    [
+      {
+        config: {
+          prefix: 'tw-',
+        },
+      },
+      {
+        handler({ addUtilities }) {
+          addUtilities({
+            '.object-fill': {
+              'object-fit': 'fill',
+            },
+            '.object-contain': {
+              'object-fit': 'contain',
+            },
+            '.object-cover': {
+              'object-fit': 'cover',
+            },
+          })
+        },
+      },
+    ],
+    makeConfig()
+  )
+
+  expect(components.length).toBe(0)
+  expect(css(utilities)).toMatchCss(`
+    @variants {
+      .object-fill {
+        object-fit: fill
+      }
+      .object-contain {
+        object-fit: contain
+      }
+      .object-cover {
+        object-fit: cover
+      }
+    }
+  `)
+})
diff --git a/__tests__/resolveConfig.test.js b/__tests__/resolveConfig.test.js
index b63a4831c..27d267345 100644
--- a/__tests__/resolveConfig.test.js
+++ b/__tests__/resolveConfig.test.js
@@ -1234,3 +1234,480 @@ test('custom properties are multiplied by -1 for negative values', () => {
     variants: {},
   })
 })
+
+test('more than two config objects can be resolved', () => {
+  const firstConfig = {
+    theme: {
+      extend: {
+        fontFamily: () => ({
+          code: ['Menlo', 'monospace'],
+        }),
+        colors: {
+          red: 'red',
+        },
+        backgroundColor: {
+          customBackgroundOne: '#bada55',
+        },
+        textDecorationColor: {
+          orange: 'orange',
+        },
+      },
+    },
+  }
+
+  const secondConfig = {
+    prefix: '-',
+    important: false,
+    separator: ':',
+    theme: {
+      extend: {
+        fontFamily: {
+          quote: ['Helvetica', 'serif'],
+        },
+        colors: {
+          green: 'green',
+        },
+        backgroundColor: {
+          customBackgroundTwo: '#facade',
+        },
+        textDecorationColor: theme => theme('colors'),
+      },
+    },
+  }
+
+  const thirdConfig = {
+    prefix: '-',
+    important: false,
+    separator: ':',
+    theme: {
+      extend: {
+        fontFamily: {
+          hero: ['Futura', 'sans-serif'],
+        },
+        colors: {
+          pink: 'pink',
+        },
+        backgroundColor: () => ({
+          customBackgroundThree: '#c0ffee',
+        }),
+        textDecorationColor: {
+          lime: 'lime',
+        },
+      },
+    },
+  }
+
+  const defaultConfig = {
+    prefix: '-',
+    important: false,
+    separator: ':',
+    theme: {
+      fontFamily: {
+        body: ['Arial', 'sans-serif'],
+        display: ['Georgia', 'serif'],
+      },
+      colors: {
+        blue: 'blue',
+      },
+      backgroundColor: theme => theme('colors'),
+    },
+    variants: {
+      backgroundColor: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([firstConfig, secondConfig, thirdConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: '-',
+    important: false,
+    separator: ':',
+    theme: {
+      fontFamily: {
+        body: ['Arial', 'sans-serif'],
+        display: ['Georgia', 'serif'],
+        code: ['Menlo', 'monospace'],
+        quote: ['Helvetica', 'serif'],
+        hero: ['Futura', 'sans-serif'],
+      },
+      colors: {
+        red: 'red',
+        green: 'green',
+        blue: 'blue',
+        pink: 'pink',
+      },
+      backgroundColor: {
+        red: 'red',
+        green: 'green',
+        blue: 'blue',
+        pink: 'pink',
+        customBackgroundOne: '#bada55',
+        customBackgroundTwo: '#facade',
+        customBackgroundThree: '#c0ffee',
+      },
+      textDecorationColor: {
+        red: 'red',
+        green: 'green',
+        blue: 'blue',
+        pink: 'pink',
+        orange: 'orange',
+        lime: 'lime',
+      },
+    },
+    variants: {
+      backgroundColor: ['responsive', 'hover', 'focus'],
+    },
+  })
+})
+
+test('plugin config modifications are applied', () => {
+  const userConfig = {
+    plugins: [
+      {
+        config: {
+          prefix: 'tw-',
+        },
+      },
+    ],
+  }
+
+  const defaultConfig = {
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([userConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: 'tw-',
+    important: false,
+    separator: ':',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+    plugins: userConfig.plugins,
+  })
+})
+
+test('user config takes precedence over plugin config modifications', () => {
+  const userConfig = {
+    prefix: 'user-',
+    plugins: [
+      {
+        config: {
+          prefix: 'tw-',
+        },
+      },
+    ],
+  }
+
+  const defaultConfig = {
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([userConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: 'user-',
+    important: false,
+    separator: ':',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+    plugins: userConfig.plugins,
+  })
+})
+
+test('plugin config can register plugins that also have config', () => {
+  const userConfig = {
+    plugins: [
+      {
+        config: {
+          prefix: 'tw-',
+          plugins: [
+            {
+              config: {
+                important: true,
+              },
+            },
+            {
+              config: {
+                separator: '__',
+              },
+            },
+          ],
+        },
+        handler() {},
+      },
+    ],
+  }
+
+  const defaultConfig = {
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([userConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: 'tw-',
+    important: true,
+    separator: '__',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+    plugins: userConfig.plugins,
+  })
+})
+
+test('plugin configs take precedence over plugin configs registered by that plugin', () => {
+  const userConfig = {
+    plugins: [
+      {
+        config: {
+          prefix: 'outer-',
+          plugins: [
+            {
+              config: {
+                prefix: 'inner-',
+              },
+            },
+          ],
+        },
+        handler() {},
+      },
+    ],
+  }
+
+  const defaultConfig = {
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([userConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: 'outer-',
+    important: false,
+    separator: ':',
+    theme: {
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+    plugins: userConfig.plugins,
+  })
+})
+
+test('plugin theme extensions are added even if user overrides top-level theme config', () => {
+  const userConfig = {
+    theme: {
+      width: {
+        '1px': '1px',
+      },
+    },
+    plugins: [
+      {
+        config: {
+          theme: {
+            extend: {
+              width: {
+                '2px': '2px',
+                '3px': '3px',
+              },
+            },
+          },
+        },
+        handler() {},
+      },
+    ],
+  }
+
+  const defaultConfig = {
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      width: {
+        sm: '1rem',
+        md: '2rem',
+        lg: '3rem',
+      },
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([userConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      width: {
+        '1px': '1px',
+        '2px': '2px',
+        '3px': '3px',
+      },
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+    plugins: userConfig.plugins,
+  })
+})
+
+test('user theme extensions take precedence over plugin theme extensions with the same key', () => {
+  const userConfig = {
+    theme: {
+      extend: {
+        width: {
+          xl: '6rem',
+        },
+      },
+    },
+    plugins: [
+      {
+        config: {
+          theme: {
+            extend: {
+              width: {
+                xl: '4rem',
+              },
+            },
+          },
+        },
+        handler() {},
+      },
+    ],
+  }
+
+  const defaultConfig = {
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      width: {
+        sm: '1rem',
+        md: '2rem',
+        lg: '3rem',
+      },
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+  }
+
+  const result = resolveConfig([userConfig, defaultConfig])
+
+  expect(result).toEqual({
+    prefix: '',
+    important: false,
+    separator: ':',
+    theme: {
+      width: {
+        sm: '1rem',
+        md: '2rem',
+        lg: '3rem',
+        xl: '6rem',
+      },
+      screens: {
+        mobile: '400px',
+      },
+    },
+    variants: {
+      appearance: ['responsive'],
+      borderCollapse: [],
+      borderColors: ['responsive', 'hover', 'focus'],
+    },
+    plugins: userConfig.plugins,
+  })
+})
diff --git a/resolveConfig.js b/resolveConfig.js
index 776aa3ba4..ecd5bf1fd 100644
--- a/resolveConfig.js
+++ b/resolveConfig.js
@@ -1,6 +1,6 @@
 const resolveConfigObjects = require('./lib/util/resolveConfig').default
 const defaultConfig = require('./stubs/defaultConfig.stub.js')
 
-module.exports = function resolveConfig(config) {
-  return resolveConfigObjects([config, defaultConfig])
+module.exports = function resolveConfig(...configs) {
+  return resolveConfigObjects([...configs, defaultConfig])
 }
diff --git a/src/index.js b/src/index.js
index b86050c2e..9dd2ab582 100644
--- a/src/index.js
+++ b/src/index.js
@@ -55,10 +55,9 @@ const getConfigFunction = config => () => {
     })
   }
 
-  return resolveConfig([
-    _.isObject(config) ? _.get(config, 'config', config) : require(config),
-    defaultConfig,
-  ])
+  const configObject = _.isObject(config) ? _.get(config, 'config', config) : require(config)
+
+  return resolveConfig([configObject, defaultConfig])
 }
 
 const plugin = postcss.plugin('tailwind', config => {
diff --git a/src/lib/substituteTailwindAtRules.js b/src/lib/substituteTailwindAtRules.js
index 3aa181d29..6ceb38aa1 100644
--- a/src/lib/substituteTailwindAtRules.js
+++ b/src/lib/substituteTailwindAtRules.js
@@ -8,7 +8,7 @@ function updateSource(nodes, source) {
 }
 
 export default function(
-  config,
+  _config,
   { base: pluginBase, components: pluginComponents, utilities: pluginUtilities }
 ) {
   return function(css) {
diff --git a/src/util/processPlugins.js b/src/util/processPlugins.js
index c59af2918..1dcd7f627 100644
--- a/src/util/processPlugins.js
+++ b/src/util/processPlugins.js
@@ -1,6 +1,7 @@
 import _ from 'lodash'
 import postcss from 'postcss'
 import Node from 'postcss/lib/node'
+import isFunction from 'lodash/isFunction'
 import escapeClassName from '../util/escapeClassName'
 import generateVariantFunction from '../util/generateVariantFunction'
 import parseObjectStyles from '../util/parseObjectStyles'
@@ -28,7 +29,9 @@ export default function(plugins, config) {
   const getConfigValue = (path, defaultValue) => _.get(config, path, defaultValue)
 
   plugins.forEach(plugin => {
-    plugin({
+    const handler = isFunction(plugin) ? plugin : _.get(plugin, 'handler', () => {})
+
+    handler({
       postcss,
       config: getConfigValue,
       theme: (path, defaultValue) => getConfigValue(`theme.${path}`, defaultValue),
diff --git a/src/util/resolveConfig.js b/src/util/resolveConfig.js
index 41e41526d..4ad99126b 100644
--- a/src/util/resolveConfig.js
+++ b/src/util/resolveConfig.js
@@ -1,7 +1,10 @@
+import some from 'lodash/some'
 import mergeWith from 'lodash/mergeWith'
 import isFunction from 'lodash/isFunction'
+import isUndefined from 'lodash/isUndefined'
 import defaults from 'lodash/defaults'
 import map from 'lodash/map'
+import get from 'lodash/get'
 import toPath from 'lodash/toPath'
 import negateValue from './negateValue'
 
@@ -23,18 +26,47 @@ function value(valueToResolve, ...args) {
   return isFunction(valueToResolve) ? valueToResolve(...args) : valueToResolve
 }
 
+function mergeThemes(themes) {
+  const theme = (({ extend: _, ...t }) => t)(
+    themes.reduce((merged, t) => {
+      return defaults(merged, t)
+    }, {})
+  )
+
+  return {
+    ...theme,
+
+    // In order to resolve n config objects, we combine all of their `extend` properties
+    // into arrays instead of objects so they aren't overridden.
+    extend: themes.reduce((merged, { extend }) => {
+      return mergeWith(merged, extend, (mergedValue, extendValue) => {
+        if (isUndefined(mergedValue)) {
+          return [extendValue]
+        }
+
+        if (Array.isArray(mergedValue)) {
+          return [extendValue, ...mergedValue]
+        }
+
+        return [extendValue, mergedValue]
+      })
+    }, {}),
+  }
+}
+
 function mergeExtensions({ extend, ...theme }) {
   return mergeWith(theme, extend, (themeValue, extensions) => {
-    if (!isFunction(themeValue) && !isFunction(extensions)) {
+    // The `extend` property is an array, so we need to check if it contains any functions
+    if (!isFunction(themeValue) && !some(extensions, isFunction)) {
       return {
         ...themeValue,
-        ...extensions,
+        ...Object.assign({}, ...extensions),
       }
     }
 
     return (resolveThemePath, utils) => ({
       ...value(themeValue, resolveThemePath, utils),
-      ...value(extensions, resolveThemePath, utils),
+      ...Object.assign({}, ...extensions.map(e => value(e, resolveThemePath, utils))),
     })
   })
 }
@@ -62,16 +94,40 @@ function resolveFunctionKeys(object) {
   }, {})
 }
 
+function extractPluginConfigs(configs) {
+  let allConfigs = []
+
+  configs.forEach(config => {
+    allConfigs = [...allConfigs, config]
+
+    const plugins = get(config, 'plugins', [])
+
+    if (plugins.length === 0) {
+      return
+    }
+
+    plugins.forEach(plugin => {
+      allConfigs = [...allConfigs, ...extractPluginConfigs([get(plugin, 'config', {})])]
+    })
+  })
+
+  return allConfigs
+}
+
 export default function resolveConfig(configs) {
+  const allConfigs = extractPluginConfigs(configs)
+
   return defaults(
     {
-      theme: resolveFunctionKeys(mergeExtensions(defaults({}, ...map(configs, 'theme')))),
+      theme: resolveFunctionKeys(
+        mergeExtensions(mergeThemes(map(allConfigs, t => get(t, 'theme', {}))))
+      ),
       variants: (firstVariants => {
         return Array.isArray(firstVariants)
           ? firstVariants
-          : defaults({}, ...map(configs, 'variants'))
-      })(defaults({}, ...map(configs)).variants),
+          : defaults({}, ...map(allConfigs, 'variants'))
+      })(defaults({}, ...map(allConfigs)).variants),
     },
-    ...configs
+    ...allConfigs
   )
 }