diff --git a/esphome/components/uart/__init__.py b/esphome/components/uart/__init__.py
index 06208dc621..65a9a3eaf8 100644
--- a/esphome/components/uart/__init__.py
+++ b/esphome/components/uart/__init__.py
@@ -1,7 +1,8 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome import pins, automation
-from esphome.const import CONF_BAUD_RATE, CONF_ID, CONF_RX_PIN, CONF_TX_PIN, CONF_UART_ID, CONF_DATA
+from esphome.const import CONF_BAUD_RATE, CONF_ID, CONF_RX_PIN, CONF_TX_PIN, CONF_UART_ID, \
+    CONF_DATA, CONF_RX_BUFFER_SIZE
 from esphome.core import CORE, coroutine
 
 uart_ns = cg.esphome_ns.namespace('uart')
@@ -44,6 +45,7 @@ CONFIG_SCHEMA = cv.All(cv.Schema({
     cv.Required(CONF_BAUD_RATE): cv.int_range(min=1),
     cv.Optional(CONF_TX_PIN): pins.output_pin,
     cv.Optional(CONF_RX_PIN): validate_rx_pin,
+    cv.Optional(CONF_RX_BUFFER_SIZE, default=256): cv.validate_bytes,
     cv.Optional(CONF_STOP_BITS, default=1): cv.one_of(1, 2, int=True),
     cv.Optional(CONF_DATA_BITS, default=8): cv.int_range(min=5, max=8),
     cv.Optional(CONF_PARITY, default="NONE"): cv.enum(UART_PARITY_OPTIONS, upper=True)
@@ -61,6 +63,7 @@ def to_code(config):
         cg.add(var.set_tx_pin(config[CONF_TX_PIN]))
     if CONF_RX_PIN in config:
         cg.add(var.set_rx_pin(config[CONF_RX_PIN]))
+    cg.add(var.set_rx_buffer_size(config[CONF_RX_BUFFER_SIZE]))
     cg.add(var.set_stop_bits(config[CONF_STOP_BITS]))
     cg.add(var.set_data_bits(config[CONF_DATA_BITS]))
     cg.add(var.set_parity(config[CONF_PARITY]))
diff --git a/esphome/components/uart/uart.h b/esphome/components/uart/uart.h
index 5528da1d5f..dedfdd74af 100644
--- a/esphome/components/uart/uart.h
+++ b/esphome/components/uart/uart.h
@@ -19,7 +19,7 @@ const char *parity_to_str(UARTParityOptions parity);
 class ESP8266SoftwareSerial {
  public:
   void setup(int8_t tx_pin, int8_t rx_pin, uint32_t baud_rate, uint8_t stop_bits, uint32_t nr_bits,
-             UARTParityOptions parity);
+             UARTParityOptions parity, size_t rx_buffer_size);
 
   uint8_t read_byte();
   uint8_t peek_byte();
@@ -44,7 +44,7 @@ class ESP8266SoftwareSerial {
 
   uint32_t bit_time_{0};
   uint8_t *rx_buffer_{nullptr};
-  size_t rx_buffer_size_{512};
+  size_t rx_buffer_size_;
   volatile size_t rx_in_pos_{0};
   size_t rx_out_pos_{0};
   uint8_t stop_bits_;
@@ -93,6 +93,7 @@ class UARTComponent : public Component, public Stream {
 
   void set_tx_pin(uint8_t tx_pin) { this->tx_pin_ = tx_pin; }
   void set_rx_pin(uint8_t rx_pin) { this->rx_pin_ = rx_pin; }
+  void set_rx_buffer_size(size_t rx_buffer_size) { this->rx_buffer_size_ = rx_buffer_size; }
   void set_stop_bits(uint8_t stop_bits) { this->stop_bits_ = stop_bits; }
   void set_data_bits(uint8_t nr_bits) { this->nr_bits_ = nr_bits; }
   void set_parity(UARTParityOptions parity) { this->parity_ = parity; }
@@ -108,6 +109,7 @@ class UARTComponent : public Component, public Stream {
 #endif
   optional<uint8_t> tx_pin_;
   optional<uint8_t> rx_pin_;
+  size_t rx_buffer_size_;
   uint32_t baud_rate_;
   uint8_t stop_bits_;
   uint8_t nr_bits_;
diff --git a/esphome/components/uart/uart_esp32.cpp b/esphome/components/uart/uart_esp32.cpp
index cb6ac843d1..e18f9c5b1f 100644
--- a/esphome/components/uart/uart_esp32.cpp
+++ b/esphome/components/uart/uart_esp32.cpp
@@ -81,6 +81,7 @@ void UARTComponent::setup() {
   int8_t tx = this->tx_pin_.has_value() ? *this->tx_pin_ : -1;
   int8_t rx = this->rx_pin_.has_value() ? *this->rx_pin_ : -1;
   this->hw_serial_->begin(this->baud_rate_, get_config(), rx, tx);
+  this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
 }
 
 void UARTComponent::dump_config() {
@@ -90,6 +91,7 @@ void UARTComponent::dump_config() {
   }
   if (this->rx_pin_.has_value()) {
     ESP_LOGCONFIG(TAG, "  RX Pin: GPIO%d", *this->rx_pin_);
+    ESP_LOGCONFIG(TAG, "  RX Buffer Size: %u", this->rx_buffer_size_);
   }
   ESP_LOGCONFIG(TAG, "  Baud Rate: %u baud", this->baud_rate_);
   ESP_LOGCONFIG(TAG, "  Bits: %u", this->nr_bits_);
diff --git a/esphome/components/uart/uart_esp8266.cpp b/esphome/components/uart/uart_esp8266.cpp
index 59a08677b5..40975b6e5e 100644
--- a/esphome/components/uart/uart_esp8266.cpp
+++ b/esphome/components/uart/uart_esp8266.cpp
@@ -52,18 +52,22 @@ void UARTComponent::setup() {
   if (this->tx_pin_.value_or(1) == 1 && this->rx_pin_.value_or(3) == 3) {
     this->hw_serial_ = &Serial;
     this->hw_serial_->begin(this->baud_rate_, config);
+    this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
   } else if (this->tx_pin_.value_or(15) == 15 && this->rx_pin_.value_or(13) == 13) {
     this->hw_serial_ = &Serial;
     this->hw_serial_->begin(this->baud_rate_, config);
+    this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
     this->hw_serial_->swap();
   } else if (this->tx_pin_.value_or(2) == 2 && this->rx_pin_.value_or(8) == 8) {
     this->hw_serial_ = &Serial1;
     this->hw_serial_->begin(this->baud_rate_, config);
+    this->hw_serial_->setRxBufferSize(this->rx_buffer_size_);
   } else {
     this->sw_serial_ = new ESP8266SoftwareSerial();
     int8_t tx = this->tx_pin_.has_value() ? *this->tx_pin_ : -1;
     int8_t rx = this->rx_pin_.has_value() ? *this->rx_pin_ : -1;
-    this->sw_serial_->setup(tx, rx, this->baud_rate_, this->stop_bits_, this->nr_bits_, this->parity_);
+    this->sw_serial_->setup(tx, rx, this->baud_rate_, this->stop_bits_, this->nr_bits_, this->parity_,
+                            this->rx_buffer_size_);
   }
 }
 
@@ -74,6 +78,7 @@ void UARTComponent::dump_config() {
   }
   if (this->rx_pin_.has_value()) {
     ESP_LOGCONFIG(TAG, "  RX Pin: GPIO%d", *this->rx_pin_);
+    ESP_LOGCONFIG(TAG, "  RX Buffer Size: %u", this->rx_buffer_size_);  // NOLINT
   }
   ESP_LOGCONFIG(TAG, "  Baud Rate: %u baud", this->baud_rate_);
   ESP_LOGCONFIG(TAG, "  Bits: %u", this->nr_bits_);
@@ -210,8 +215,9 @@ void ESP8266SoftwareSerial::begin() {
   // this->gpio_rx_pin_->attach_interrupt(ESP8266SoftwareSerial::gpio_intr, this, FALLING);
 }
 void ESP8266SoftwareSerial::setup(int8_t tx_pin, int8_t rx_pin, uint32_t baud_rate, uint8_t stop_bits, uint32_t nr_bits,
-                                  UARTParityOptions parity) {
+                                  UARTParityOptions parity, size_t rx_buffer_size) {
   this->bit_time_ = F_CPU / baud_rate;
+  this->rx_buffer_size_ = rx_buffer_size;
   this->stop_bits_ = stop_bits;
   this->nr_bits_ = nr_bits;
   this->parity_ = parity;
diff --git a/esphome/const.py b/esphome/const.py
index b244d5681a..95b2da36d7 100644
--- a/esphome/const.py
+++ b/esphome/const.py
@@ -395,6 +395,7 @@ CONF_RTD_WIRES = 'rtd_wires'
 CONF_RUN_CYCLES = 'run_cycles'
 CONF_RUN_DURATION = 'run_duration'
 CONF_RW_PIN = 'rw_pin'
+CONF_RX_BUFFER_SIZE = 'rx_buffer_size'
 CONF_RX_ONLY = 'rx_only'
 CONF_RX_PIN = 'rx_pin'
 CONF_SAFE_MODE = 'safe_mode'
diff --git a/tests/test1.yaml b/tests/test1.yaml
index 115dc73464..dae8cfdb21 100644
--- a/tests/test1.yaml
+++ b/tests/test1.yaml
@@ -135,6 +135,7 @@ uart:
   parity: NONE
   data_bits: 8
   stop_bits: 1
+  rx_buffer_size: 512
 
 ota:
   safe_mode: True