This is a partial list of unnumbered minor planets for principal provisional designations assigned during 16–30 September 2003. Since this period yielded a high number of provisional discoveries, it is further split into several standalone pages. , a total of 483 bodies remain unnumbered for this period. Objects for this year are listed on the following pages: A–E · F–G · H–L · M–R · Si · Sii · Siii · Siv · T · Ui · Uii · Uiii · Uiv · V · Wi · Wii and X–Y. Also see previous and next year.
S
|- id="2003 SG390" bgcolor=#fefefe
| 0 || || MBA-I || 18.0 || data-sort-value="0.75" | 750 m || multiple || 2000–2021 || 05 Jan 2021 || 143 || align=left | Disc.: SDSSAlt.: 2010 VD73, 2012 KW20 || |- id="2003 SK390" bgcolor=#d6d6d6 | 4 || || MBA-O || 17.8 || 1.5 km || multiple || 2003–2019 || 07 Sep 2019 || 14 || align=left | Disc.: SDSSAdded on 17 January 2021 || |- id="2003 SO390" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.3 || 3.1 km || multiple || 1997–2021 || 11 Jan 2021 || 126 || align=left | Disc.: SDSS || |- id="2003 SP390" bgcolor=#fefefe | 0 || || MBA-I || 18.75 || data-sort-value="0.53" | 530 m || multiple || 2003–2021 || 30 Nov 2021 || 98 || align=left | Disc.: SDSSAdded on 22 July 2020 || |- id="2003 SS390" bgcolor=#fefefe | 0 || || MBA-I || 19.1 || data-sort-value="0.45" | 450 m || multiple || 2003–2020 || 14 Nov 2020 || 32 || align=left | Disc.: SDSS || |- id="2003 SU390" bgcolor=#fefefe | 0 || || MBA-I || 18.21 || data-sort-value="0.68" | 680 m || multiple || 2003–2021 || 05 Oct 2021 || 94 || align=left | Disc.: SDSSAlt.: 2016 CW58, 2017 MJ2 || |- id="2003 SW390" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.18 || 3.2 km || multiple || 2003–2022 || 27 Jan 2022 || 149 || align=left | Disc.: SDSSAlt.: 2006 FH48, 2010 CF243, 2014 TE31, 2014 UH38, 2014 UW275 || |- id="2003 SX390" bgcolor=#E9E9E9 | 1 || || MBA-M || 18.00 || 1.4 km || multiple || 2003–2021 || 29 Sep 2021 || 51 || align=left | Disc.: SDSS || |- id="2003 SD391" bgcolor=#FA8072 | 2 || || MCA || 20.2 || data-sort-value="0.27" | 270 m || multiple || 2003–2020 || 09 Oct 2020 || 23 || align=left | Disc.: SDSSAdded on 17 January 2021 || |- id="2003 SG391" bgcolor=#E9E9E9 | 1 || || MBA-M || 17.96 || 1.4 km || multiple || 2003–2021 || 10 Aug 2021 || 37 || align=left | Disc.: SDSSAdded on 21 August 2021 || |- id="2003 SH391" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.53 || 2.8 km || multiple || 2001–2022 || 25 Jan 2022 || 131 || align=left | Disc.: SDSSAlt.: 2006 DA191 || |- id="2003 SL391" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.7 || 2.5 km || multiple || 2003–2021 || 15 Jan 2021 || 84 || align=left | Disc.: SDSSAlt.: 2010 DZ90 || |- id="2003 SO391" bgcolor=#d6d6d6 | 1 || || MBA-O || 17.8 || 1.5 km || multiple || 2003–2019 || 05 Jul 2019 || 33 || align=left | Disc.: SDSSAlt.: 2014 WZ250 || |- id="2003 SP391" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.6 || 2.7 km || multiple || 2003–2021 || 16 Jan 2021 || 123 || align=left | Disc.: SDSS || |- id="2003 SR391" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.88 || 1.5 km || multiple || 2003–2021 || 04 Oct 2021 || 58 || align=left | Disc.: SDSSAlt.: 2005 EL111, 2005 EN333 || |- id="2003 SU391" bgcolor=#E9E9E9 | – || || MBA-M || 18.8 || data-sort-value="0.97" | 970 m || single || 4 days || 30 Sep 2003 || 6 || align=left | Disc.: SDSS || |- id="2003 SW391" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.5 || 1.3 km || multiple || 2003–2020 || 18 Oct 2020 || 80 || align=left | Disc.: SDSS || |- id="2003 SC392" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.28 || 3.1 km || multiple || 2001–2021 || 07 Apr 2021 || 265 || align=left | Disc.: SDSSAlt.: 2011 FH78 || |- id="2003 SD392" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.5 || 1.3 km || multiple || 2003–2020 || 16 Nov 2020 || 106 || align=left | Disc.: SDSSAlt.: 2015 HA38 || |- id="2003 SF392" bgcolor=#d6d6d6 | 0 || || MBA-O || 17.2 || 2.0 km || multiple || 2003–2019 || 05 Nov 2019 || 54 || align=left | Disc.: SDSS || |- id="2003 SL392" bgcolor=#E9E9E9 | 0 || || MBA-M || 17.18 || 1.5 km || multiple || 2001–2022 || 26 Jan 2022 || 186 || align=left | Disc.: SDSS || |- id="2003 SO392" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.0 || 3.5 km || multiple || 2003–2020 || 17 Nov 2020 || 149 || align=left | Disc.: SDSSAlt.: 2014 QH150 || |- id="2003 ST392" bgcolor=#d6d6d6 | 0 || || MBA-O || 16.3 || 3.1 km || multiple || 2001–2020 || 18 Dec 2020 || 97 || align=left | Disc.: SDSSAlt.: 2017 HQ37 || |- id="2003 SU392" bgcolor=#d6d6d6 | 3 || || MBA-O || 17.5 || 1.8 km || multiple || 2003–2019 || 02 Nov 2019 || 46 || align=left | Disc.: SDSSAlt.: 2014 WN473 || |- id="2003 SW392" bgcolor=#E9E9E9 | 0 || || MBA-M || 18.59 || data-sort-value="0.80" | 800 m || multiple || 2003–2021 || 02 Dec 2021 || 40 || align=left | Disc.: SDSSAdded on 24 December 2021 || |- id="2003 SX392" bgcolor=#fefefe | 0 || || MBA-I || 19.0 || data-sort-v