diff --git a/DESCRIPTION b/DESCRIPTION
index 0765e5661..c34babb23 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -54,6 +54,7 @@ Collate:
     'serialize.R'
     'serialized_tests.R'
     'style_guides.R'
+    'style_rmd.R'
     'styler.R'
     'token-create.R'
     'transform.R'
diff --git a/R/style_rmd.R b/R/style_rmd.R
new file mode 100644
index 000000000..dd78e5ca1
--- /dev/null
+++ b/R/style_rmd.R
@@ -0,0 +1,78 @@
+#' Transform code from R or Rmd files
+#'
+#' A wrapper for [utf8::transform_lines_enc()] which initiates the styling of
+#' either R or Rmd files by passing the relevant transformer function for each
+#' case.
+#'
+#' @inheritParams utf8::transform_lines_enc
+#' @param ... Further arguments passed to `utf8::transform_lines_enc()`.
+transform_code <- function(path, fun, verbose, ...) {
+  if (grepl("\\.R$", path, ignore.case = TRUE)) {
+    utf8::transform_lines_enc(path, fun = fun, ...)
+  } else if (grepl("\\.Rmd$", path, ignore.case = TRUE)) {
+    utf8::transform_lines_enc(path, fun = partial(transform_rmd, transformer_fun = fun), ...)
+  } else {
+    stop(path, " is not an R or Rmd file")
+  }
+}
+
+#' Transform Rmd contents
+#'
+#' Applies the supplied transformer function to code chunks identified within
+#' an Rmd file and recombines the resulting (styled) code chunks with the text
+#' chunks.
+#'
+#' @param lines A character vector of lines from an Rmd file
+#' @param transformer_fun A styler transformer function
+#' @importFrom purrr flatten_chr
+transform_rmd <- function(lines, transformer_fun) {
+  chunks <- identify_chunks(lines)
+  chunks$r_chunks <- map(chunks$r_chunks, transformer_fun)
+
+  map2(chunks$text_chunks, c(chunks$r_chunks, list(character(0))), c) %>%
+    flatten_chr()
+}
+
+
+#' Identify chunks within Rmd contents
+#'
+#' Identifies the code and text chunks within an Rmd file, and returns these
+#' as a nested list.
+#'
+#' @param lines a character vector of lines from an Rmd file
+#'
+#' @importFrom purrr map2
+#' @importFrom rlang seq2
+identify_chunks <- function(lines) {
+  pattern <- get_knitr_pattern(lines)
+  if (is.null(pattern$chunk.begin) || is.null(pattern$chunk.end)) {
+    stop("Unrecognized chunk pattern!", call. = FALSE)
+  }
+
+  starts <- grep(pattern$chunk.begin, lines, perl = TRUE)
+  ends <- grep(pattern$chunk.end, lines, perl = TRUE)
+
+  if (length(starts) != length(ends)) {
+    stop("Malformed file!", call. = FALSE)
+  }
+
+  r_chunks <- map2(starts, ends, ~lines[seq2(.x + 1, .y - 1)])
+
+  text_chunks <- map2(c(1, ends), c(starts, length(lines)), ~lines[seq2(.x, .y)])
+
+  lst(r_chunks, text_chunks)
+}
+
+#' Get chunk pattern
+#'
+#' Determine a regex pattern for identifying R code chunks.
+#'
+#' @inheritParams identify_chunks
+get_knitr_pattern <- function(lines) {
+  pattern <- knitr:::detect_pattern(lines, "rmd")
+  if (!is.null(pattern)) {
+    knitr::all_patterns[[pattern]]
+  } else {
+    NULL
+  }
+}
diff --git a/R/transform.R b/R/transform.R
index 3204f44ec..bbb596de8 100644
--- a/R/transform.R
+++ b/R/transform.R
@@ -27,9 +27,9 @@ transform_files <- function(files, transformers) {
   invisible(changed)
 }
 
-#' Transform a file an give customized message
+#' Transform a file and output a customized message
 #'
-#' Wraps `utf8::transform_lines_enc()` and gives customized messages.
+#' Wraps `utf8::transform_lines_enc()` and outputs customized messages.
 #' @param max_char_path The number of characters of the longest path. Determines
 #'   the indention level of `message_after`.
 #' @param message_before The message to print before the path.
@@ -51,7 +51,7 @@ transform_file <- function(path,
   n_spaces_before_message_after <-
     max_char_after_message_path - char_after_path
   message(message_before, path, ".", appendLF = FALSE)
-  changed <- utf8::transform_lines_enc(path, fun = fun, verbose = verbose, ...)
+  changed <- transform_code(path, fun = fun, verbose = verbose, ...)
 
   message(
     rep(" ", max(0, n_spaces_before_message_after)),
diff --git a/R/ws.R b/R/ws.R
index 9b4c786c0..c25a57956 100644
--- a/R/ws.R
+++ b/R/ws.R
@@ -145,16 +145,6 @@ style_file <- function(path,
                        transformers = style(...)) {
   withr::with_dir(
     dirname(path),
-    prettify_one(transformers, basename(path))
+    transform_files(basename(path), transformers)
   )
 }
-
-#' Prettify one R file
-#'
-#' This is a helper function for style_dir.
-#' @inheritParams style_dir
-#' @param path The path to a file that should be styled.
-prettify_one <- function(transformers, path) {
-  if (!grepl("\\.[Rr]$", path)) stop(path, " is not a .R file")
-  transform_files(path, transformers)
-}
diff --git a/man/get_knitr_pattern.Rd b/man/get_knitr_pattern.Rd
new file mode 100644
index 000000000..042f04753
--- /dev/null
+++ b/man/get_knitr_pattern.Rd
@@ -0,0 +1,14 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/style_rmd.R
+\name{get_knitr_pattern}
+\alias{get_knitr_pattern}
+\title{Get chunk pattern}
+\usage{
+get_knitr_pattern(lines)
+}
+\arguments{
+\item{lines}{a character vector of lines from an Rmd file}
+}
+\description{
+Determine a regex pattern for identifying R code chunks.
+}
diff --git a/man/identify_chunks.Rd b/man/identify_chunks.Rd
new file mode 100644
index 000000000..daf52ed70
--- /dev/null
+++ b/man/identify_chunks.Rd
@@ -0,0 +1,15 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/style_rmd.R
+\name{identify_chunks}
+\alias{identify_chunks}
+\title{Identify chunks within Rmd contents}
+\usage{
+identify_chunks(lines)
+}
+\arguments{
+\item{lines}{a character vector of lines from an Rmd file}
+}
+\description{
+Identifies the code and text chunks within an Rmd file, and returns these
+as a nested list.
+}
diff --git a/man/prettify_one.Rd b/man/prettify_one.Rd
deleted file mode 100644
index 084b2945d..000000000
--- a/man/prettify_one.Rd
+++ /dev/null
@@ -1,18 +0,0 @@
-% Generated by roxygen2: do not edit by hand
-% Please edit documentation in R/ws.R
-\name{prettify_one}
-\alias{prettify_one}
-\title{Prettify one R file}
-\usage{
-prettify_one(transformers, path)
-}
-\arguments{
-\item{transformers}{A set of transformer functions. This argument is most
-conveniently constructed via the \code{style} argument and \code{...}. See
-'Examples'.}
-
-\item{path}{The path to a file that should be styled.}
-}
-\description{
-This is a helper function for style_dir.
-}
diff --git a/man/transform_code.Rd b/man/transform_code.Rd
new file mode 100644
index 000000000..a5768de67
--- /dev/null
+++ b/man/transform_code.Rd
@@ -0,0 +1,23 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/style_rmd.R
+\name{transform_code}
+\alias{transform_code}
+\title{Transform code from R or Rmd files}
+\usage{
+transform_code(path, fun, verbose, ...)
+}
+\arguments{
+\item{path}{A vector of file paths.}
+
+\item{fun}{A function that returns a character vector.}
+
+\item{verbose}{Should the function show a message with a list of changed
+files?}
+
+\item{...}{Further arguments passed to \code{utf8::transform_lines_enc()}.}
+}
+\description{
+A wrapper for \code{\link[utf8:transform_lines_enc]{utf8::transform_lines_enc()}} which initiates the styling of
+either R or Rmd files by passing the relevant transformer function for each
+case.
+}
diff --git a/man/transform_file.Rd b/man/transform_file.Rd
index e617999d0..9ff703eff 100644
--- a/man/transform_file.Rd
+++ b/man/transform_file.Rd
@@ -2,7 +2,7 @@
 % Please edit documentation in R/transform.R
 \name{transform_file}
 \alias{transform_file}
-\title{Transform a file an give customized message}
+\title{Transform a file and output a customized message}
 \usage{
 transform_file(path, fun, verbose = FALSE, max_char_path,
   message_before = "", message_after = " [DONE]",
@@ -29,5 +29,5 @@ any file was transformed.}
 \item{...}{Further arguments passed to \code{utf8::transform_lines_enc()}.}
 }
 \description{
-Wraps \code{utf8::transform_lines_enc()} and gives customized messages.
+Wraps \code{utf8::transform_lines_enc()} and outputs customized messages.
 }
diff --git a/man/transform_rmd.Rd b/man/transform_rmd.Rd
new file mode 100644
index 000000000..5a89f0edf
--- /dev/null
+++ b/man/transform_rmd.Rd
@@ -0,0 +1,18 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/style_rmd.R
+\name{transform_rmd}
+\alias{transform_rmd}
+\title{Transform Rmd contents}
+\usage{
+transform_rmd(lines, transformer_fun)
+}
+\arguments{
+\item{lines}{A character vector of lines from an Rmd file}
+
+\item{transformer_fun}{A styler transformer function}
+}
+\description{
+Applies the supplied transformer function to code chunks identified within
+an Rmd file and recombines the resulting (styled) code chunks with the text
+chunks.
+}
diff --git a/tests/testthat/public-api/xyzfile_rmd/random.Rmd b/tests/testthat/public-api/xyzfile_rmd/random.Rmd
new file mode 100644
index 000000000..c5528fc5e
--- /dev/null
+++ b/tests/testthat/public-api/xyzfile_rmd/random.Rmd
@@ -0,0 +1,18 @@
+Some text
+```{r}
+# Some R code
+f <- function(x) {
+  x
+}
+```
+More text
+```{r}
+# More R code
+g <- function(y) {
+  y
+}
+```
+Final text
+```{r}
+1 + 2
+```
diff --git a/tests/testthat/public-api/xyzfile_rmd/random2.Rmd b/tests/testthat/public-api/xyzfile_rmd/random2.Rmd
new file mode 100644
index 000000000..f372022ce
--- /dev/null
+++ b/tests/testthat/public-api/xyzfile_rmd/random2.Rmd
@@ -0,0 +1,18 @@
+```{r}
+# Start with chunk
+```
+Some text before empty chunk
+```{r}
+
+```
+Final text before longer code chunk
+This text chunk has multiple lines
+```{r}
+# random
+this(is_a_call(x))
+if (x) {
+  r()
+  a    <- 3
+  bcds <- 5
+}
+```
diff --git a/tests/testthat/public-api/xyzfile_rmd/random3.Rmd b/tests/testthat/public-api/xyzfile_rmd/random3.Rmd
new file mode 100644
index 000000000..5ea72f5f4
--- /dev/null
+++ b/tests/testthat/public-api/xyzfile_rmd/random3.Rmd
@@ -0,0 +1,17 @@
+Some text
+```{r}
+# Some R code
+f <- function(x) {
+  x
+}
+```
+More text before malformed chunk
+# More R code
+g <- function(y) {
+  y
+}
+```
+Final text
+```{r}
+1 + 2
+```
diff --git a/tests/testthat/public-api/xyzfile_rmd/random4.Rmd b/tests/testthat/public-api/xyzfile_rmd/random4.Rmd
new file mode 100644
index 000000000..b898ad3b5
--- /dev/null
+++ b/tests/testthat/public-api/xyzfile_rmd/random4.Rmd
@@ -0,0 +1,17 @@
+Some text
+```{r}
+# Some R code
+f <- function(x) {
+  x
+}
+```
+More text
+```{r}
+# More R code which is invalid
+g <- function(y) {
+  y
+```
+Final text
+```{r}
+1 + 2
+```
diff --git a/tests/testthat/test-public_api.R b/tests/testthat/test-public_api.R
index d0ff2c653..df0cc44fb 100644
--- a/tests/testthat/test-public_api.R
+++ b/tests/testthat/test-public_api.R
@@ -27,3 +27,23 @@ test_that("styler does not return error when there is no file to style", {
 
 # styling active region cannot be tested automatically since
 # rstudioapi::insertText() needs the context id.
+
+context("public API - Rmd")
+
+test_that("styler can style Rmd file", {
+  expect_false(
+    style_file(testthat_file("public-api", "xyzfile_rmd", "random.Rmd"), strict = FALSE)
+  )
+  expect_false(
+    style_file(testthat_file("public-api", "xyzfile_rmd", "random2.Rmd"), strict = FALSE)
+  )
+})
+
+test_that("styler handles malformed Rmd file and invalid R code in chunk", {
+  expect_warning(
+    style_file(testthat_file("public-api", "xyzfile_rmd", "random3.Rmd"), strict = FALSE)
+  )
+  expect_warning(
+    style_file(testthat_file("public-api", "xyzfile_rmd", "random4.Rmd"), strict = FALSE)
+  )
+})