Whitby, a large suburb of Porirua City, New Zealand, located along much of the southern shore of the Pauatahanui Inlet of Porirua Harbour was comprehensively planned in the 1960s (when still in Hutt County) and it has been continuously developed since, with current landscaping and expansion in the hills behind the eastern part of Whitby to facilitate the future growth of the suburb.

The name of the suburb itself, as well as the nautical theme of neighbourhood and street names, are drawn from the life and career of the Pacific explorer James Cook. The bicentennial of his first (1769) visit to New Zealand occurred when the development of Whitby started.

The suburb is commercially centred on the Whitby Shopping Centre, containing almost all the retail businesses in Whitby.

In 1967 some 3,180 acres (1,290 ha) of farmland was purchased by a consortium for a new residential development, to be similar to North American new towns; with a population growing to 16,000 in four "neighbourhoods", each focussed on a primary school. Following a town planning appeal hearing in 1974 this became two "neighbourhoods", Adventure and Endeavour.

The first sections in the 01 subdivision were sold by auction in 1970. By May 1971 eight homes were occupied (5 Spinnaker Drive was first); and by 1972, 203 sections had been sold and 62 of the 117 houses built were occupied. By 1998 some 2000 houses had been built. The consortium developed a village centre and a golf course, and operated a commuter bus service from 1 February 1973. The New Zealand Institution of Engineers gave the development their 1978 Environmental Award for an engineering work exemplifying care for and consideration of environmental values.

The original area was part of the Horokiri riding of Hutt County, and some of the later land was in Porirua City. In 1988 the Local Government Commission decided that all of Whitby should come under the Porirua City Council. The Community Developments Consortium (originally Huapai Properties) had partners Fletcher Mainline, Jubilee Investments (part of the Todd Group) and the National Mutual Life Association.

Whitby, comprising the statistical areas of Whitby, Postgate, Endeavour East and Endeavour West, covers 6.67 km (2.58 sq mi). It had an estimated population of 12,230 as of June 2024, with a population density of 1,834 people per km.

Historical population

Year	Pop.	±% p.a.
2006	8,364	—
2013	8,844	+0.80%
2018	10,413	+3.32%
Source:

Before the 2023 census, Whitby had a smaller boundary, covering 6.45 km (2.49 sq mi). Using that boundary, Whitby had a population of 10,413 at the 2018 New Zealand census, an increase of 1,569 people (17.7%) since the 2013 census, and an increase of 2,049 people (24.5%) since the 2006 census. There were 3,468 households, comprising 5,112 males and 5,292 females, giving a sex ratio of 0.97 males per female, with 2,304 people (22.1%) aged under 15 years, 1,674 (16.1%) aged 15 to 29, 5,118 (49.2%) aged 30 to 64, and 1,308 (12.6%) aged 65 or older.

Ethnicities were 83.8% European/Pākehā, 10.3% Māori, 6.7% Pasifika, 8.6% Asian, and 2.8% other ethnicities. People may identify with more than one ethnicity.

The percentage of people born overseas was 26.4, compared with 27.1% nationally.

Although some people chose not to answer the census's question about religious affiliation, 51.2% had no religion, 38.2% were Christian, 0.2% had Māori religious beliefs, 1.6% were Hindu, 0.5% were Muslim, 0.8% were Buddhist and 2.0% had other religions.

Of those at least 15 years old, 2,520 (31.1%) people had a bachelor's or higher degree, and 765 (9.4%) people had no formal qualifications. 2,709 people (33.4%) earned over $70,000 compared to 17.2% nationally. The employment status of those at least 15 was that 4,812 (59.3%) people were employed full-time, 1,083 (13.4%) were part-time, and 252 (3.1%) were unemployed.

Individual statistical areas in 2018

Name	Area (km)	Population	Density (per km)	Households	Median age	Median income
Postgate	1.29	2,754	2,135	927	34.1 years	$47,600
Whitby	2.04	3,042	1,491	1,059	41.1 years	$44,900
Endeavour	3.12	4,617	1,480	1,482	39.8 years	$54,500
New Zealand					37.4 years	$31,800

Buses servicing the area;

Number 230

Runs between The Crowsnest (Whitby) and Porirua Railway Station (Porirua), stopping at following stops (among others);

• The Crowsnest
• Spinnaker Drive at Hicks Close
• Aotea College opposite Okowai Road
• Porirua Station - Stop B

Number 236

Runs Between Navigation Drive (Whitby) and Porirua Railway Station (Porirua), stopping at following stops (among others);

• Navigation Drive
• Whitby Lakes (Upper Lake)
• Spinnaker Drive at Hicks Close
• Paremata Road (near 132)
• Paremata Station (bus stop)
• Oak Avenue (opposite 10)
• RNZ Police College - Papakowhai Road
• Porirua Station - Stop B

Postgate School is a co-educational state primary school for Year 1 to 8 students, with a roll of 305 as of August 2024.

Adventure School is a co-educational state primary school for Year 1 to 8 students, with a roll of 487.

Discovery School is a co-educational state primary school for Year 1 to 8 students, with a roll of 504.

Whitby Collegiate is a co-educational private secondary school for Year 7 to 13 students, with a roll of 325 as of August 2024.

Whitby Independent College was foundeded in January 2004 by David Bradford, CEO and owner of Whitby Coastal Estates Ltd. The company had recently closed the Duck Creek Golf Course that it owned. It was decided to redesign and convert the clubhouse and proshop for the first 4 classrooms and administration. The project was designed by Gina Jones of Accent Architects.

Whitby Independent was the Wellington region's first new independent secondary school in 100 years. The college was initially managed by Anita Baker, a senior executive of Whitby Coastal Estates Ltd. Anita later became Mayor of Porirua City.

3 years later the school was purchased by Samuel Marsden Collegiate School and renamed Samuel Marsden Collegiate Whitby. A new classroom block was completed in mid-2007 which includes a large art room.

On 1 July 2019 Samuel Marsden Collegiate School Trust Board announced it had made the decision to close Marsden School Whitby at the end of the 2019 school year. On 9 August 2019 Fiso Group Ltd announced plans to acquire the school. The sale of Marsden Whitby to Fiso Investment Group Ltd was finalised on 10 December 2019. The school became Whitby Collegiate at the start of the 2020 academic year.

Preschool education is available from Discovery Kindergarten, Adventure Kindergarten and Mana Montessori Preschool.

The nearest public secondary school is Aotea College in Aotea.

41°07′01″S 174°53′35″E / 41.11694°S 174.89306°E / -41.11694; 174.89306