diff --git a/R/cran.R b/R/cran.R
index 7201fe6..bed04ce 100644
--- a/R/cran.R
+++ b/R/cran.R
@@ -134,7 +134,7 @@ find_exports_without_examples <- function(lines) {
         line <- lines[i]
 
         # Start of doc block
-        if (grepl("^#'", line)) {
+        if (grepl("^##?'", line)) {
             if (!in_doc_block) {
                 in_doc_block <- TRUE
                 has_export <- FALSE
@@ -143,12 +143,12 @@ find_exports_without_examples <- function(lines) {
             }
 
             # Check for export tag
-            if (grepl("^#'\\s*@export", line)) {
+            if (grepl("^##?'\\s*@export", line)) {
                 has_export <- TRUE
             }
 
             # Check for examples tag
-            if (grepl("^#'\\s*@examples", line)) {
+            if (grepl("^##?'\\s*@examples", line)) {
                 has_examples <- TRUE
             }
         } else if (in_doc_block) {
@@ -183,14 +183,14 @@ find_dontrun_examples <- function(lines) {
     for (i in seq_along(lines)) {
         line <- lines[i]
 
-        if (grepl("^#'", line)) {
+        if (grepl("^##?'", line)) {
             if (!in_doc_block) {
                 in_doc_block <- TRUE
                 has_export <- FALSE
                 has_dontrun <- FALSE
             }
 
-            if (grepl("^#'\\s*@export", line)) {
+            if (grepl("^##?'\\s*@export", line)) {
                 has_export <- TRUE
             }
 
@@ -226,25 +226,25 @@ find_long_example_lines <- function(lines, filename) {
     for (i in seq_along(lines)) {
         line <- lines[i]
 
-        if (!grepl("^#'", line)) {
+        if (!grepl("^##?'", line)) {
             in_examples <- FALSE
             next
         }
 
-        if (grepl("^#'\\s*@examples", line)) {
+        if (grepl("^##?'\\s*@examples", line)) {
             in_examples <- TRUE
             next
         }
 
         # Other tags end the examples block
-        if (grepl("^#'\\s*@[a-zA-Z]", line)) {
+        if (grepl("^##?'\\s*@[a-zA-Z]", line)) {
             in_examples <- FALSE
             next
         }
 
         if (in_examples) {
             # Strip the #' prefix to get the actual example content
-            content <- sub("^#'\\s?", "", line)
+            content <- sub("^##?'\\s?", "", line)
             if (nchar(content) > 100) {
                 found <- c(found,
                            paste0(filename, ":", i, " (", nchar(content), " chars)"))
diff --git a/R/parse.R b/R/parse.R
index 45f9721..716d304 100644
--- a/R/parse.R
+++ b/R/parse.R
@@ -14,7 +14,7 @@ parse_file <- function(file) {
     lines <- readLines(file, encoding = "UTF-8", warn = FALSE)
 
     # Find documentation blocks (consecutive #' lines)
-    doc_lines <- grep("^#'", lines)
+    doc_lines <- grep("^##?'", lines)
 
     if (length(doc_lines) == 0) {
         return(list())
@@ -43,8 +43,8 @@ parse_file <- function(file) {
     result <- list()
 
     for (block_lines in blocks) {
-        # Extract the comment text (strip #' prefix)
-        comment_text <- sub("^#'\\s?", "", lines[block_lines])
+        # Extract the comment text (strip #' or ##' prefix)
+        comment_text <- sub("^##?'\\s?", "", lines[block_lines])
 
         # Find the object definition after the block. Blank lines and plain
         # comments between the block and its object are allowed; another #'
@@ -52,12 +52,12 @@ parse_file <- function(file) {
         next_line <- max(block_lines) + 1
 
         while (next_line <= length(lines) &&
-            !grepl("^\\s*#'", lines[next_line]) &&
+            !grepl("^\\s*##?'", lines[next_line]) &&
             grepl("^\\s*(#|$)", lines[next_line])) {
             next_line <- next_line + 1
         }
 
-        if (next_line > length(lines) || grepl("^\\s*#'", lines[next_line])) {
+        if (next_line > length(lines) || grepl("^\\s*##?'", lines[next_line])) {
             warning("Documentation block at ", basename(file), ":",
                     block_lines[1], " is not followed by an object ",
                     "definition; its tags are ignored.", call. = FALSE)
diff --git a/inst/tinytest/test_parse.R b/inst/tinytest/test_parse.R
index 533ee16..d1b01c8 100644
--- a/inst/tinytest/test_parse.R
+++ b/inst/tinytest/test_parse.R
@@ -110,3 +110,33 @@ expect_equal(length(big$formals$names), 30L)
 expect_equal(big$formals$names[30], "a30")
 expect_true(all(grepl("= NULL$", big$formals$usage)))
 unlink(tmp)
+
+# ESS-style ##' comments parse like #' (PR #27).
+tmp <- tempfile(fileext = ".R")
+writeLines(c(
+  "##' Add one",
+  "##' @param x A number.",
+  "##' @export",
+  "add_one <- function(x) x + 1"
+), tmp)
+blocks <- tinyrox:::parse_file(tmp)
+expect_equal(length(blocks), 1)
+expect_equal(blocks[[1]]$object, "add_one")
+unlink(tmp)
+
+# The orphaned-block detector must recognise ##' too, so a stray ##' block
+# can't bleed into the next object (the #18 regression for double-hash).
+tmp <- tempfile(fileext = ".R")
+writeLines(c(
+  "##' Orphaned block (its object was moved away)",
+  "##' @export",
+  "",
+  "##' Real",
+  "##' @export",
+  "real_fn <- function() 1"
+), tmp)
+expect_warning(blocks <- tinyrox:::parse_file(tmp),
+               pattern = "not followed by an object definition")
+expect_equal(length(blocks), 1)
+expect_equal(blocks[[1]]$object, "real_fn")
+unlink(tmp)